Metastatic carcinoma of unknown primary: diagnostic approach using immunohistochemistry

Gastric Metastasis Mimicking Early Gastric Cancer from Invasive Ductal Carcinoma of the Breast: Case Report and Literature Review

Backgound and Objectives: Gastric metastasis from invasive ductal breast cancer (BC) is rare. It mainly occurs in patients with lobular BC. The occurrence of multiple metastases is typically observed several years after the primary diagnosis. Endoscopic findings of gastric metastasis of the BC were usually the linitis plastic type. Case presentation: A 72-year-old women who underwent right modified radical mastectomy (MRM) 10 month ago was referred after being diagnosed with early gastric cancer (EGC) during systemic chemotherapy. EGC type I was found at gastric fundus, and pathologic finding showed poorly differentiated adenocarcinoma. Metachronous double primary tumor EGC was considered. Management and Outcome: A laparoscopic total gastrectomy was performed, and postoperative pathology revealed submucosa invasion and two lymph node metastases. A pathologic review that focused on immunohistochemical studies of selected antibodies such as GATA binding protein 3 (GATA3), gross cystic disease fluid protein-15 (GCDFP-15), cytokeratin 7 (CK7) was performed again, comparing previous results. As a result, gastric metastasis from BC was diagnosed. After totally laparoscopic total gastrectomy, palliative first-line chemotherapy with paclitaxel/CDDP was performed. Two months after gastrectomy, she was diagnosed with para-aortic lymph node metastasis and multiple bone metastases. She expired six months after gastrectomy. Conclusions: Gastric metastasis from invasive ductal carcinoma of the breast, which is clinically manifested as EGC, is a very rare condition. If there is a history of BC, careful pathological review will be required.

A case of disseminated peritoneal metastases after 2-year conservative treatment for intramucosal colon carcinoma due to a perforation during endoscopic submucosal dissection

A 70-year-old man was admitted to our hospital for the treatment of a large granular-type laterally spreading tumor in the splenic flexure of the descending colon. The preoperative diagnosis was intramucosal colon carcinoma and endoscopic submucosal dissection was performed. During treatment, a small perforation occurred accidentally. After conservative treatment with endoscopic suturing, the patient was discharged without additional surgery. The pathological diagnosis was an intramucosal carcinoma. One year after treatment, no local recurrence was observed on endoscopy, and abdominal computed tomography showed no obvious metastasis. Two years later, fluorodeoxyglucose-positron emission tomography/computed tomography, laparoscopic findings, and histopathologic findings by experimental excision of omentum revealed several disseminated peritoneal metastases from previously treated colon carcinoma. To the best of our knowledge, this is the first report of peritoneal dissemination after a small perforation during endoscopic submucosal dissection and conservative therapy for early-stage colon carcinoma. This report suggests the possibility of tumor dissemination in patients with small perforations during endoscopic procedures. Endoscopists should be aware of these rare potential risks and perform later surveillance carefully.

A case of laparoscopic lymphadenectomy for adenocarcinoma of unknown primary incidentally detected as a solitary enlarged lymph node along the common hepatic artery

BACKGROUND

Even in cancer of unknown primary (CUP), which is rare clinical condition, solitary anterosuperior lymph node (LN) along the common hepatic artery (No.8a LN) enlargement diagnosed as metastatic adenocarcinoma has never been reported.

CASE PRESENTATION

A 68-year-old Japanese male, with a history of early gastric cancer that had been completely treated by endoscopic submucosal dissection 26 years ago, was detected a single enlarged nodule along the common hepatic artery, No.8a LN, incidentally by computed tomography performed for monitoring of interstitial pneumonia. Endoscopic ultra-sound-guided fine needle aspiration revealed that this nodule was adenocarcinoma suggestive of metastasis, but other imaging studies, including upper and lower gastrointestinal endoscopy, positron emission tomography, and ultrasonography did not detect any primary cancer. We have finally diagnosed as the LN metastasis of CUP and performed laparoscopic lymphadenectomy for this tumor. The tumor was approximately 5 cm in size, was in close proximity to the pancreas, and involved part of the right gastric artery and vein. LNs in the No.5 and No.8a areas, including this tumor, were dissected laparoscopically, and radical resection was achieved. The patient had no postoperative complication and was discharged on postoperative day 10. Immunohistopathological findings revealed that the tumor was poorly differentiated adenocarcinoma, and different from the histology of gastric cancer resected 26 years ago, although the tumor was suggestive of gastrointestinal origin. Imaging studies performed 2 and 6 months after discharge also did not reveal a primary site.

CONCLUSION

We reported a case of solitary No.8a LN adenocarcinoma of CUP. For diagnostic and therapeutic purposes, radical resection is recommended for single enlarged intra-abdominal LN of CUP.

Patterns of Immunoreactivity with TTF-1 Antibodies 8G7G3/1 and SPT24 Suggest Distinct Immunoprofiles Between Most Pulmonary and Nonpulmonary Small Cell Carcinomas

Introduction. Small cell carcinoma can arise from various sites. Herein, we analyze the ability of 2 thyroid transcription factor-1 (TTF-1) antibodies (SPT24 and 8G7G3/1) to separate pulmonary from nonpulmonary small cell carcinoma. Materials and Methods. We analyzed 26 pulmonary and 83 nonpulmonary small cell carcinomas, and 14 Merkel cell carcinomas. Each tumor was stained with SPT24 and 8G7G3/1. Extent of nuclear staining was scored as diffuse (>50%), focal (11%-50%), rare (1%-10%), or negative (<1%). Results. All pulmonary small cell carcinomas were positive for SPT24 and 8G7G3/1. Four Merkel cell carcinomas (29%) were positive for SPT24 (ranging from rare-to-diffuse), while 2 (14%) showed rare expression with 8G7G3/1. For nonpulmonary small cell carcinomas, 69 (83%) were positive for SPT24 and 40 (48%) were positive for 8G7G3/1. For SPT24 positive tumors, the extent of 8G7G3/1 expression was equal in 17 (25%) and less in 52 tumors (75%), including 29 (42%) that were negative for 8G7G3/1. No nonpulmonary small cell carcinoma had more staining with 8G7G3/1 compared to SPT24. The differences in staining between 8G7G3/1 and SPT24 in the nonpulmonary cohort were statistically significant (P < 0.0001) with no significant difference between primary and metastatic lesions for 8G7G3/1 (P  =  0.66) or SPT24 (P  =  0.77). Conclusion. Most pulmonary small cell carcinomas are diffusely positive for both SPT24 and 8G7G3/1, whereas most nonpulmonary small cell carcinomas exhibit focal-to-no staining with 8G7G3/1 and significantly less staining with 8G7G3/1 compared to SPT24. However, these trends are not absolute and should be interpreted in conjunction with clinical and radiological findings.

Primary mucinous adenocarcinoma of the urethra: A contemporary clinicopathologic analysis of 17 patients

Mucinous adenocarcinoma of the urethra is rare. Here we performed a contemporary clinicopathologic analysis of this entity in both male and female patients. All cases with secondary tumors involving the urethra were excluded. Clinicopathologic parameters and follow up was obtained. Seventeen patients were included in the study, 9/17 (53 %) male and 8/17 (47 %) female. The mean patient age was 68 years (range: 53-88 years). The majority (11/17, 65 %) of patients were African American, with an even greater incidence (7/8, 87 %) in female patients. In male patients, prostatic urethra was the most common part of the urethra (6/9, 67 %) where the tumor arose from. Immunohistochemical stains were performed in 11/17 (65 %) tumors and were positive for CK20 (11/11, 100 %), CDX2 (11/12, 92 %), CK7 (8/9, 88 %), GATA3 (3/8, 37 %) and negative for NKX3.1, PSA, p63, PAX8, and Beta-Catenin. In resection specimens, tumors were categorized as pT2 (3/11, 27 %), pT3 (1/11, 9 %), and pT4 (7/11, 64 %). Lymph node status was categorized as pN0 (6/9, 67 %), pN1 (1/9, 11 %), and pN2 (2/9, 22 %). Available follow up data showed 7/13 (54 %) patients developed recurrence after surgical resection and chemotherapy, of which 3/7 (43 %) died of widespread metastatic disease. It is critical for pathologists and urologic oncologists to be aware of this entity in both male and female patients in view of potential diagnostic pitfalls, prognosis, and therapeutic implications.

Rare axillary cancer of unknown primary originating from the breast of a 64‑year‑old male patient: A case report and literature review

Cancers of unknown primary (CUPs) are a heterogeneous group of tumors characterized by a difficult diagnosis. The primitive tumor remains unknown, whereas metastases are the most common manifestation. Occult male breast cancers are very rare types of CUPs. The present study describes the case of a 64-year-old man affected by a CUP of presumed mammary origin. The aim of the article and the present review was to focus on their management. To the best of our knowledge, only thirteen cases have been reported in the literature. Because no specific guidelines are available, various approaches have been applied, influencing the treatment and the prognosis of patients with CUP.

Comprehensive analysis of cancer of unknown primary and recommendation of a histological and immunohistochemical diagnostic strategy from China

BACKGROUND

Previous studies on cancer of unknown primary (CUP) mainly focus on treatment and prognosis in western populations and lacked clinical evaluation of different IHC markers, so this study aimed to evaluate characteristics of CUP and recommend a diagnostic strategy from a single center in China.

METHODS AND RESULTS

Data of 625 patients with CUP were retrospectively collected and reviewed. The patients ranged in age from 20 to 91 years, with a female-to-male ratio of 1.3:1. The predominant histological type was poor or undifferentiated adenocarcinomas (308; 49.3%). The results of Canhelp-Origin molecular testing for the identification of the tissue of origin in 262 of 369 patients (71.0%) were considered predictable (similarity score > 45), with the most common predicted primary tumor site being the breast (57, 21.8%). Unpredictable molecular results correlated with more aggressive clinical parameters and poor survival. Thee positivity rates of several targeted antibodies (GATA3, GCDFP15, TTF1, Napsin A, and PAX8), based on the clinically predicted site, were lower than those reported for the corresponding primary tumors. Nonetheless, TRPS1 and INSM1 were reliable markers of predicted breast carcinoma (75.0%) and neuroendocrine tumors (83.3%), respectively. P16 expression, as well as HPV and EBER testing contributed significantly to the diagnosis of squamous cell carcinomas. Survival analysis revealed that older ages (> 57), ≥ 3 metastatic sites, non-squamous cell carcinomas, bone/liver/lung metastases, unpredictable molecular results, and palliative treatment correlated with poor overall survival.

CONCLUSIONS

We recommend a CUP diagnostic strategy involving the use of targeted antibody panels as per histological findings that is potentially applicable in clinical practice. The markers TRPS1, INSM1, and P16 expression, as well as HPV and EBER testing are particularly valuable in this aspect. Molecular testing is also predictive of survival rates.

Histopathological Evaluation and Molecular Diagnostic Tests for Peritoneal Metastases with Unknown Primary Site-a Review

Cancer of unknown primary (CUP) is a well-studied entity with guidelines available for the management of patients with CUP. The peritoneum represents one of the metastatic sites in CUP, and peritoneal metastases (PM) could present as CUP. PM of unknown origin remains a poorly studied clinical entity. There is only one series of 15 cases, one population-based study, and few other case reports on this subject. Studies on CUP, in general, cover some common tumour histological types like adenocarcinomas and squamous carcinomas. Some of these tumours may have a good prognosis though majority have high-grade disease with a poor long-term outcome. Some of the histological tumour types commonly seen in the clinical scenario of PM like mucinous carcinoma have not been studied. In this review, we divide PM into five histological types-adenocarcinomas, serous carcinomas, mucinous carcinomas, sarcomas and other rare varieties. We provide algorithms to identify the primary tumour site using immunohistochemistry when imaging, and endoscopy fails to establish the primary tumour site. The role of molecular diagnostic tests for PM or unknown origin is also discussed. Current literature on site-specific systemic therapy based on gene expression profiling does not show a clear benefit of this approach over empirical systemic therapies.

[CUP syndrome-diagnostics from the perspective of pathology]

PROBLEM

Histologic and immunohistologic workup of tumor material from metastases of a previously unknown primary tumor is important for identifying their origin, but is often insufficient for this purpose without clinical oncologic and radiologic evaluation.

PROCEDURE

In the initial cancer of unknown primary (CUP) situation, histologic and immunohistochemical workup together with clinicoradiologic correlations contribute significantly to the identification of the primary tumor. There are now accepted guidelines to follow when there is an initial CUP situation. Molecular diagnostic tools can be used to investigate changes at the nucleic acid level, which can provide clues about the primary tumor, including potential targets for therapy. If, despite broad and interdisciplinary diagnostics, it is not possible to identify the primary tumor, the diagnosis is CUP syndrome. If a true CUP situation is present, it is important to assign the tumor to a tumor class or a specific therapy-sensitive subgroup as best as possible so that the best possible treatment can be given. However, for a final assignment to a primary tumor or a final classification as CUP, a comparison with medical oncological and imaging findings is indispensable.

CONCLUSION

When CUP is suspected, close interdisciplinary collaboration between pathology, medical oncology, and imaging is essential to achieve a viable classification as CUP or identification of a presumptive primary tumor, in the interest of providing the most specific and effective therapy for affected individuals.

Cancers of Unknown Primary: A Descriptive Study in the U.S. Military Health System

INTRODUCTION

Cancers of unknown primary (CUP) are defined as histologically confirmed metastatic cancers that do not have an identified primary site of origin despite an appropriate diagnostic workup. Although accessibility to and quality of medical care influence diagnosis of cancer including CUP, previous studies describing CUP have generally been conducted in patients with various accessibilities to care. This study aimed to describe the demographic, histologic, and temporal trend characteristics of CUP patients in the DoD Cancer Registry of the Military Health System (MHS), which provides universal health care access, reducing the potential effects of accessibility to care on research results.

MATERIALS AND METHODS

The data were obtained from the DoD's Automated Central Tumor Registry (ACTUR), which collects cancer data from beneficiaries who were diagnosed or received treatment in the MHS. We described the demographic and histologic distributions in CUP patients aged 18 years or older diagnosed from 1987 to 2013. We calculated the proportion of CUP patients among all metastatic cancers and the most common histologic categories of those tumors. We then evaluated whether the proportion of histologic types changed over time.

RESULTS

CUP comprised 13.3% of all metastatic cancers in ACTUR during the study period. The majority of CUP within ACTUR was moderately and well-differentiated adenocarcinoma (51.3%) and poorly differentiated carcinomas (23.2%) followed by squamous cell carcinomas (12.5%). The percentages of CUP among metastasized cancers of the same histologic category ranged 12%-15% for moderately and well-differentiated adenocarcinomas, squamous cell, and poorly differentiated carcinomas, and 41%-46% for malignant neuroendocrine carcinomas and undifferentiated neoplasms. However, the percentages varied by sex, race, and age for certain pathologies. The proportion of CUP patients among all metastatic cancer patients has steadily declined from 22.4% to 8.3% from 1987 to 2013.

CONCLUSION

The proportion and trends of CUP in the ACTUR were generally consistent with other descriptive CUP studies. This study provides a description of CUP in a health care system with universal access in the USA and provides a foundation for future studies on CUP.

Wnt Family Member 9b (Wnt9b) Is a Sensitive and Specific Marker for Triple-negative Breast Carcinoma Including Metaplastic Carcinoma

Wnt9b was recently identified as a highly sensitive and specific marker for breast carcinomas. Due to the limited number of triple-negative breast carcinomas (TNBCs) in previous study, we further explored Wnt9b's utility in breast carcinoma, especially in TNBCs including metaplastic carcinomas. We systematically evaluated Wnt9b expression on tissue microarrays (TMAs) from 413 breast carcinomas, 208 urothelial carcinomas, 102 endometrial carcinomas, 109 cholangiocarcinomas, 192 ovarian carcinomas, 48 lung adenocarcinomas, 69 colorectal adenocarcinomas, and 78 melanomas, and whole tissue section (WTS) from 20 human epidermal growth factor receptor 2-positive, 34 nonmetaplastic TNBCs, and 67 invasive metaplastic carcinomas. The results showed Wnt9b was highly expressed in breast carcinomas (91% on TMA and 98% on WTS) and in nonmetaplastic TNBCs (91% on TMA and 97% on WTS), but almost completely negative in other tested tumor types. Wnt9b was also highly expressed in metaplastic carcinomas (80%), significantly higher than GATA3 (56%) and SOX10 (48%), but slightly lower than TRPS1 (90%). In summary, our results demonstrate that Wnt9b is a highly sensitive marker for breast carcinomas, including TNBCs and metaplastic carcinomas. Further, we compared its utility with other breast markers including TRPS1, GATA3, and SOX10 in metaplastic carcinomas.

A generational comparison for unfavorable cancer of unknown primary in a single institute over 20 years

BACKGROUND

The prognosis of unfavorable cancer of unknown primary is extremely poor. This is the first report to compared the treatment results between generations of CUP and examined prognostic factors.

METHODS

This retrospective single-center cohort study enrolled 68 patients with newly diagnosed unfavorable cancer of unknown primary at Taipei Veteran General Hospital from 2017 to 2020 as study cohort and 167 patients from 2000 to 2009 as historical cohort.

RESULTS

The median overall survival was 4.3 months in the study cohort (95% CI, 2.7-6.2 months) and 4.5 months in the historical cohort (95% CI, 3.0-5.5 months; p = 0.858). Eleven patients in the study cohort received immunotherapy. The disease control rates were 45%. Multivariate analysis showed that an Eastern Cooperative Oncology Group score > 1 and a C-reactive protein level > 1 correlated with poor survival. A new prognostic stratification model was constructed by using Eastern Cooperative Oncology Group score and C-reactive protein values. The good-, intermediate-, and poor-risk groups had distinct median overall survival of 18.3, 7.0 and 1.2 months, respectively (area under the curve, 0.817; p < 0.001).

CONCLUSION

The outcome of unfavorable cancer of unknown primary has not changed much over the last 20 years. The application of a new prognostic stratification model can further stratify unfavorable cancer of unknown primary.

Diagnostic accuracy of SATB2 in identifying primary and metastatic colorectal carcinoma: a comparative immunohistochemical study

Special AT-rich sequence-binding protein 2 (SATB2) is a new marker that could identify the colonic origin, but whether its expression is preserved in metastatic colorectal carcinomas (CRCs) remains unclear. This study was designed to investigate SATB2 validity in the identification of CRC either alone or in combination with caudal-type homeobox 2 (CDX2) and/or cytokeratin 20 (CK20). Moreover, we examined the concordance of SATB2 expression in primary CRC and paired metastatic specimen. Immunohistochemical expression of SATB2, CDX2 and CK20 was evaluated in primary CRC, 50 paired metastatic CRC and 80 non-CRC specimens. This study demonstrated that the ideal SATB2 cut-off value for recognising colonic from non-colonic origin was 10%. SATB2 was more sensitive and specific than CK20. However, it was more specific but less sensitive than CDX2. Analysing the combined markers expression, SATB2 and CDX2 combination revealed better sensitivity, specificity and larger area under curve compared to SATB2 alone, CDX2 alone and combined CDX2 and CK20. Moreover, SATB2 was able to retain its expression at the metastatic sites. SATB2 was totally concordant between primary CRC and their paired metastatic sites (concordance rate = 100%) with perfect level of agreement. SATB2 could be considered as an accurate diagnostic marker of primary and metastatic CRC. SATB2 and CDX2 is the best combination serving the highest sensitivity and specificity in detection of CRC.

Approach to Fine Needle Aspiration of Adrenal Gland Lesions

Adrenal gland lesions are present in 1% to 5% of patients and are most commonly identified incidentally on abdominal imaging. Fine needle aspiration (FNA) cytology plays an important role in the initial workup of adrenal gland nodules, especially in patients with a known history of malignancy. The most common reason for adrenal gland FNA is to differentiate benign adrenal lesions, such as adrenal cortical adenoma, from metastatic malignancy. However, there is a significant cytomorphologic overlap between primary and metastatic adrenal neoplasms. This review focuses on the current state of adrenal gland FNA cytology, with an emphasis on distinguishing adrenocortical adenoma from carcinoma and adrenal cortical neoplasms from metastatic malignancies. The role of immunohistochemistry in specifically diagnosing adrenal neoplasms is discussed. Proposed diagnostic classification systems for adrenal gland FNA cytology are also described.

New Genetic Technologies in Diagnosis and Treatment of Cancer of Unknown Primary

Simple Summary

The NGS and other molecular techniques creates huge hopes for effective CUP patients treatment and to select them for molecularly targeted therapies (agnostic therapies) and immunotherapy. Development of diagnostic technologies and biologically targeted therapies could make CUP’ patients access to modern therapies and change their outcome.

Abstract

Cancer of unknown primary (CUP) represents a rare oncological and heterogeneous disease in which one or more metastases are present, but the location of the primary site is unknown. Pathological diagnosis, using immunohistochemistry, of such metastatic materials is challenging and frequently does not allow for determining the tissue of origin (ToO). The selection of systemic therapy in patients with CUP is usually based on empiric grounds, and the prognosis is generally unfavourable. New molecular techniques could identify the tissue of origin and be used to select systemic agnostic therapies in various malignancies with specific molecular abnormalities. Targetable driver mutations or gene rearrangements in cancer cells may be identified using various molecular assays, of which particularly valuable are next-generation sequencing techniques. These assays may identify tumour sources and allow personalized treatments. However, current guidelines for CUP management do not recommend routine testing of gene expression and epigenetic factors. This is mainly due to the insufficient evidence supporting the improvement of CUP’s prognosis by virtue of this approach. This review summarizes the advantages and disadvantages of new genetic techniques in CUP diagnostics and proposes updating the recommendations for CUP management.

SEOM-GECOD clinical guideline for unknown primary cancer (2021)

Cancer of unknown primary site (CUP) is defined as a heterogeneous group of tumors that appear as metastases, and of which standard diagnostic work-up fails to identify the origin. It is considered a separate entity with a specific biology, and nowadays molecular characteristics and the determination of actionable mutations may be important in a significant group of patients. In this guide, we summarize the diagnostic, therapeutic, and possible new developments in molecular medicine that may help us in the management of this unique disease entity.

Avoiding "False Positive" and "False Negative" Immunohistochemical Results in Breast Pathology

Immunohistochemistry (IHC) plays an important role in the evaluation of breast pathology specimens to provide both diagnostic and prognostic/therapeutic information. Although most IHCs used in breast pathology can be easily interpreted, pitfalls do exist, especially in some uncommon scenarios. This review intends to focus on the challenging areas such as the interpretation of myoepithelial cell markers in differentiating benign proliferation and in situ carcinoma from invasive carcinoma, lobular cell markers in differentiating lobular from ductal carcinoma, cytokeratin and other markers in diagnosing metaplastic carcinoma, and breast tissue origin markers in diagnosing breast primary carcinoma. The challenges in interpreting prognostic and predictive markers will be also discussed.

Image-guided percutaneous needle biopsy for the diagnosis of cancer of unknown primary

AIM

This study aimed to assess the efficacy of image-guided percutaneous needle biopsy in patients with suspected cancer of unknown primary.

METHODS

We conducted a retrospective observational study. Among 291 patients with suspected cancer of unknown primary who were referred to our institution between April 2011 and March 2014, 89 who underwent image-guided percutaneous needle biopsy and 27 who underwent surgical biopsy were defined as the image-guided percutaneous needle biopsy group and the surgical group, respectively. Patient backgrounds, diagnostic yields, promptness of biopsy, general anesthesia rates, and severe complication rates were compared between the two groups.

RESULTS

There was no significant difference in the patient backgrounds of the two groups. The diagnostic yields were 98.9% (95% confidence interval, 93.9%-99.8%) in the image-guided percutaneous needle biopsy group and 100% (95% confidence interval, 87.5%-100%) in the surgical biopsy group (no significant difference; p = 1.0). The mean time to biopsy was significantly shorter (6.5 days vs. 21.3 days; p < .0001) and general anesthesia was used in significantly fewer patients (0% vs. 40.7%; p < .0001) in the image-guided percutaneous needle biopsy group. There was no significant difference in the rate of serious complications between the two groups (p = 1.0).

CONCLUSION

As a biopsy procedure for patients with suspected cancer of unknown primary, image-guided percutaneous needle biopsy is equally diagnostic and safe for surgical biopsy and might be preferable to surgical biopsy in terms of promptness and not requiring general anesthesia.

Identification of the most specific markers to differentiate primary pulmonary carcinoma from metastatic gastrointestinal carcinoma to the lung

Background

A number of biomarkers have the potential of differentiating between primary lung tumours and secondary lung tumours from the gastrointestinal tract, however, a standardised panel for that purpose does not exist yet. We aimed to identify the smallest panel that is most sensitive and specific at differentiating between primary lung tumours and secondary lung tumours from the gastrointestinal tract.

Methods

A total of 170 samples were collected, including 140 primary and 30 non-primary lung tumours and staining for CK7, Napsin-A, TTF1, CK20, CDX2, and SATB2 was performed via tissue microarray. The data was then analysed using univariate regression models and a combination of multivariate regression models and Receiver Operating Characteristic (ROC) curves.

Results

Univariate regression models confirmed the 6 biomarkers’ ability to independently predict the primary outcome (p < 0.001). Multivariate models of 2-biomarker combinations identified 11 combinations with statistically significant odds ratios (ORs) (p < 0.05), of which TTF1/CDX2 had the highest area under the curve (AUC) (0.983, 0.960–1.000 95% CI). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 75.7, 100, 100, and 37.5% respectively. Multivariate models of 3-biomarker combinations identified 4 combinations with statistically significant ORs (p < 0.05), of which CK7/CK20/SATB2 had the highest AUC (0.965, 0.930–1.000 95% CI). The sensitivity, specificity, PPV, and NPV were 85.1, 100, 100, and 41.7% respectively. Multivariate models of 4-biomarker combinations did not identify any combinations with statistically significant ORs (p < 0.05).

Conclusions

The analysis identified the combination of CK7/CK20/SATB2 to be the smallest panel with the highest sensitivity (85.1%) and specificity (100%) for predicting tumour origin with an ROC AUC of 0.965 (p < 0.001; SE: 0.018, 0.930–1.000 95% CI).

Supplementary Information

The online version contains supplementary material available at 10.1186/s13000-021-01184-2.

Clinicopathologic Features of Gynecologic Malignancies Presenting Clinically as Colonic Malignancies

OBJECTIVES

To systematically evaluate gynecologic malignancies (adnexal or uterine) causing gastrointestinal (GI) signs (eg, mass on colonoscopy) or symptoms (eg, bloody stools) clinically mimicking a GI primary malignancy.

METHODS

The archives of 2 institutions were retrospectively reviewed for gynecologic malignancies clinically manifesting as colonic lesions. For each case, available radiologic, endoscopic, and histologic findings were recorded.

RESULTS

We identified 16 cases: 13 biopsies and 3 resections. The masses were localized in the rectosigmoid (14 cases [88%]), right (1 case [6%]), and transverse (1 case [6%]) colon. Gastrointestinal-type complaints included abdominal pain, weight loss, hematochezia, and obstruction; 1 case was asymptomatic and found during screening colonoscopy. Nine patients (56%) had no known prior gynecologic malignancy, and in only 2 of these patients was there some clinical suspicion of a noncolonic primary malignancy. Most cases (13 [81%]) were serous carcinoma, usually high-grade adnexal or primary peritoneal. Six cases (38%) directly extended into the colon, and 7 (44%) metastasized; route of spread was unclear in the others. Only 1 case (6%) showed mucosal involvement, and none showed desmoplasia or dirty necrosis. Four of the 13 serous carcinomas (31%) showed psammoma bodies.

CONCLUSIONS

Advanced gynecologic malignancies, most commonly serous carcinoma, can rarely manifest as GI lesions. Clues to noncolonic origin on biopsy include lack of colonic mucosal involvement/dysplasia, desmoplasia, or dirty necrosis.

Loss of SATB2 Occurs More Frequently Than CDX2 Loss in Colorectal Carcinoma and Identifies Particularly Aggressive Cancers in High-Risk Subgroups

Simple Summary

The immunohistochemical analysis of Special AT-rich sequence-binding protein 2 (SATB2) is increasingly being used to detect colorectal differentiation. Our study aimed to investigate SATB2 expression levels and the prognostic relevance of SATB2 loss in colorectal carcinoma (CRC), especially in comparison with CDX2, the standard marker of colorectal differentiation. We tested SATB2 expression in 1039 CRCs and identified SATB2 as a strong prognosticator in the overall cohort as well as in specific subcohorts, including high-risk subgroups. Compared to CDX2, SATB2 showed a higher prognostic power but was lost at a much higher frequency, generally rendering SATB2 as the less sensitive marker for colorectal differentiation compared to CDX2.

Abstract

Background: Special AT-rich sequence-binding protein 2 (SATB2) has emerged as an alternative immunohistochemical marker to CDX2 for colorectal differentiation. However, the distribution and prognostic relevance of SATB2 expression in colorectal carcinoma (CRC) have to be further elucidated. Methods: SATB2 expression was analysed in 1039 CRCs and correlated with clinicopathological and morphological factors, CDX2 expression as well as survival parameters within the overall cohort and in clinicopathological subgroups. Results: SATB2 loss was a strong prognosticator in univariate analyses of the overall cohort (p < 0.001 for all survival comparisons) and in numerous subcohorts including high-risk scenarios (UICC stage III/high tumour budding). SATB2 retained its prognostic relevance in multivariate analyses of these high-risk scenarios (e.g., UICC stage III: DSS: p = 0.007, HR: 1.95), but not in the overall cohort (DSS: p = 0.1, HR: 1.25). SATB2 loss was more frequent than CDX2 loss (22.2% vs. 10.2%, p < 0.001) and of higher prognostic relevance with only moderate overlap between SATB2/CDX2 expression groups. Conclusions: SATB2 loss is able to identify especially aggressive CRCs in high-risk subgroups. While SATB2 is the prognostically superior immunohistochemical parameter compared to CDX2 in univariate analyses, it appears to be the less sensitive marker for colorectal differentiation as it is lost more frequently.

Updates on Molecular and Biochemical Development and Progression of Prostate Cancer

Prostate cancer (PCa) represents the most commonly non-cutaneous diagnosed cancer in men worldwide and occupies a very wide area of preclinical and clinical research. Targeted therapy for any cancer depends on the understanding of the molecular bases and natural behaviour of the diseases. Despite the well-known effect of androgen deprivation on PCa, many patients develop resistance either for antiandrogen therapy or other new treatment modalities such as checkpoint inhibitors and chemotherapy. Comprehensive understanding of the development of PCa as well as of the mechanisms underlying its progression is mandatory to maximise the benefit of the current approved medications or to guide the future research for targeted therapy of PCa. The aim of this review was to provide updates on the most recent mechanisms regarding the development and the progression of PCa. According to the current understanding, future treatment strategies should include more predictive genetic and biomarker analysis to assign different patients to the expected most appropriate and effective treatment.

The cell of cancer origin provides the most reliable roadmap to its diagnosis, prognosis (biology) and therapy

Cancers arise from single transformed cells from virtually every organ of the body, divide in a relatively uncontrolled manner, and metastasize widely. A search for a "magic bullet" to precisely diagnose, characterize, and ultimately treat cancer has largely failed because cancer cells do not differ significantly from their organ-specific cells of origin. Instead of searching for genomic, epigenetic, transcriptional, and translational differences between cancers and their cells of origin, we should paradoxically focus on what cancer cells have in common with their untransformed cells of origin. This redirected search will lead to improved diagnostic and therapeutic strategies where therapeutic index considerations and drug-limiting toxicities can largely be circumvented. We cite three cancer examples that illustrate this paradigm-shifting strategy: pseudomyxoma peritonei (PP), metastasis of unknown origin (cancers of unknown primary) (MUO), and cancers that arise from potentially dispensable organs (CAD). In each of these examples, the cell of cancer origin still provides the most reliable road map to its diagnosis, prognosis (biology), and therapy.

Loss of CDX2 in colorectal cancer is associated with histopathologic subtypes and microsatellite instability but is prognostically inferior to hematoxylin-eosin-based morphologic parameters from the WHO classification

BACKGROUND

Immunohistochemical loss of CDX2 has been proposed as a biomarker of dismal survival in colorectal carcinoma (CRC), especially in UICC Stage II/III. However, it remains unclear, how CDX2 expression is related to central hematoxylin-eosin (HE)-based morphologic parameters defined by 2019 WHO classification and how its prognostic relevance is compared to these parameters.

METHODS

We evaluated CDX2 expression in 1003 CRCs and explored its prognostic relevance compared to CRC subtypes, tumour budding and WHO grade in the overall cohort and in specific subgroups.

RESULTS

CDX2-low/absent CRCs were enriched in specific morphologic subtypes, right-sided and microsatellite-instable (MSI-H) CRCs (P < 0.001) and showed worse survival characteristics in the overall cohort/UICC Stage II/III (e.g. DFS: P = 0.005) and in microsatellite stable and left-sided CRCs, but not in MSI-H or right-sided CRCs. Compared with CDX2, all HE-based markers showed a significantly better prognostic discrimination in all scenarios. In multivariate analyses including all morphologic parameters, CDX2 was not an independent prognostic factor.

CONCLUSION

CDX2 loss has some prognostic impact in univariate analyses, but its prognostic relevance is considerably lower compared to central HE-based morphologic parameters defined by the WHO classification and vanishes in multivariate analyses incorporating these factors.

Heterochronous Metastases of Lung Adenocarcinoma to Pancreas and Liver: A Case Report from Pathological Perspectives

Immunohistochemistry (IHC) is a vital tool to distinguish tumor metastases from primary lesions in addition to morphologic analysis. In this study, a 64-year-old female with a past surgical history of lung adenocarcinoma 11 years ago was presented with recurrence of liver nodular lesions after multiple surgical procedures, including the Whipple procedure for pancreatic head adenocarcinoma and cytoreductive surgery for liver metastasis. Liver biopsy and review of the previous specimens, based on IHC analyses, suggested heterochronous metastases of lung adenocarcinoma to the digestive systems in a long-time span, instead of primary pancreatic adenocarcinoma. This case demonstrates the potential for misdiagnoses from morphologic analysis alone and suggests the necessity of IHC analyses to avoid misjudgment on tumor phenotypes, when a previous oncologic history is presented.

Immunocytochemistry for diagnostic cytopathology-A practical guide

Cytological specimens, which are obtained by minimally invasive methods, are an excellent source of diagnostic material. Sometimes they are the only material available for diagnosis as well as for prognostic/predictive markers. When cytomorphology is not straightforward, ancillary tests may be required for a definitive diagnosis to guide clinical management. Immunocytochemistry (ICC) is the most common and practical ancillary tool used to reach a diagnosis when cytomorphology is equivocal, to differentiate entities with overlapping morphological features, and to determine the cell lineage and the site of origin of a metastatic neoplasm. Numerous immunomarkers are available, and some are expressed in multiple neoplasms. To rule out entities within a differential diagnosis, the use of more than one marker, sometimes panels, is necessary. ICC panels for diagnostic purposes should be customised based on the clinical context and cytomorphology, and the markers should be used judiciously to preserve material for additional tests for targeted therapies in the appropriate setting. This review offers a practical guide for the use of ICC for diagnostic cytopathology, covering the most commonly encountered non-hematolymphoid diagnostic scenarios in various body sites.

Successful Alectinib Treatment for Carcinoma of Unknown Primary with EML4-ALK Fusion Gene: A Case Report

Gene alteration in anaplastic lymphoma kinase (ALK) is rare, and the efficacy of ALK inhibitors in the treatment of carcinoma of unknown primary (CUP) with ALK alteration remains unclear. The patient was a 56-year-old woman who presented with cervical lymph node swelling. Computed tomography revealed paraaortic, perigastric, and cervical lymph node swelling; ascites; a liver lesion; and a left adrenal mass. A cervical lymph node biopsy was performed, and pathological diagnosis of an undifferentiated malignant tumor was conducted. Finally, the patient was diagnosed with CUP and treated with chemotherapy. To evaluate actionable mutations, we performed a multigene analysis, using a next-generation sequencer (FoundationOne^® CDx). It revealed that the tumor harbored an echinoderm microtubule-associated protein-like 4 (EML4) and ALK fusion gene. Additionally, immunohistochemistry confirmed ALK protein expression. Alectinib, a potent ALK inhibitor, was recommended for the patient at a molecular oncology conference at our institution. Accordingly, alectinib (600 mg/day) was administered, and the multiple lesions and symptoms rapidly diminished without apparent toxicity. The administration of alectinib continued for a period of 10 months without disease progression. Thus, ALK-tyrosine kinase inhibitors should be considered in patients with CUP harboring the EML4-ALK fusion gene.

Case Report: Next-Generation Sequencing Reveals Tumor Origin in a Female Patient With Brain Metastases

BACKGROUND

Brain metastasis mainly originates from lung cancer. Napsin A and TTF-1 factors have frequently been detected in lung adenocarcinoma cases. Brain metastasis tumors with napsin A and TTF-1 positive are easily classified as lung adenocarcinoma origin. However, some thyroid cancers also exhibit these clinical features. Besides, lung is the most common metastasis of undifferential thyroid cancer. Therefore, it requires development of novel diagnostic tools to aid in distinguishing between pulmonary and thyroid origin.

PATIENT FINDINGS

We reported a case that was initially diagnosed as brain metastatic lung cancer based on immunohistochemistry results. Analysis of next-generation sequencing (NGS) data from the brain lesion revealed that the cancer may have originated from the thyroid. We detected combo mutations in TERT promoter mutation, RET fusion and TP53, which are common in undifferential thyroid cancer (UTC), but rare for lung cancer. These results, coupled with identification of PAX8, indicated that this patient had UTC. Additionally, her three sons, despite being asymptomatic, were all diagnosed with papillary thyroid carcinoma.

SUMMARY

The patient received anlotinib treatment and showed good clinical outcomes. One month after anlotinib treatment, the pulmonary nodules were found to be controlled, and the thyroid tumor drastically reduced, and tracheal compression relieved. She continued anlotinib treatment for the following two months, but died one month later because the treatment stopped owing to financial reasons. All her sons underwent total thyroidectomy with lymph node dissection.

CONCLUSIONS

Although NGS has been reported to assist in diagnosis of the origin of some tumors, this is the first evidence of NGS for the determination of the origin of thyroid tumors. To our knowledge, this is the first time that a combination of multiple mutations has been used to help determine the origin of a tumor, compared with the previous single mutant gene. Moreover, this is the first evidence on the use of anlotinib for treatment of UTC with distant metastasis. Besides, all three sons of the patient had thyroid carcinoma in subsequent examinations, indicating high-risk for familial non-medullary thyroid cancer in UTC patients and necessity for performing thyroid ultrasound testing in other family members.

Cytokeratin 7, GATA3, and SOX-10 is a Comprehensive Panel in Diagnosing Triple Negative Breast Cancer Brain Metastases

Following lung cancer, breast cancer is the second most common metastatic tumor to the brain, of which triple-negative breast cancer (TNBC) and human epidermal growth factor receptor 2+ (HER2+) breast cancer are the most common subtypes. TNBC does not have standard immunoprofiles and can be difficult to distinguish from other metastases. A tissue microarray was created from 47 patients with breast cancer metastases to the brain and 12 paired breast primaries. Of 47 breast cancer metastases, 24 were HER2+, 14 were TNBC, and 9 were luminal. Forty-five were cytokeratin 7 (CK7) positive, 36 were GATA-binding protein 3 (GATA3) positive, 7 were Sry-related HMg-Box gene 10 (SOX-10) positive, 20 were mammaglobin positive, and 19 were gross cystic disease fluid protein 15 positive. At least one of the CK7, GATA3, or SOX-10 was positive in all TNBC metastases. A panel of CK7, GATA3, and SOX-10 is complementary in the diagnosis of breast cancer brain metastasis. SOX-10 appears to be a specific but not particularly sensitive marker in this context.

Cell-blocks and immunohistochemistry

The interpretation of results on immunostained cell-block sections has to be compared with the cumulative published data derived predominantly from formalin-fixed paraffin-embedded (FFPE) tissue sections. Because of this, it is important to recognize that the fixation and processing protocol should not be different from the routinely processed FFPE surgical pathology tissue. Exposure to non-formalin fixatives or reagents may interfere with the diagnostic immunoreactivity pattern. The immunoprofile observed on such cell-blocks, which are not processed in a manner similar to the surgical pathology specimens, may not be representative resulting in aberrant results. The field of immunohistochemistry (IHC) is advancing continuously with the standardization of many immunomarkers. A variety of technical advances such as multiplex IHC with refined methodologies and automation is increasing its role in clinical applications. The recent addition of rabbit monoclonal antibodies has further improved sensitivity. As compared to the mouse monoclonal antibodies, the rabbit monoclonal antibodies have 10 to 100 fold higher antigen affinity. Most of the scenarios involve the evaluation of coordinate immunostaining patterns in cell-blocks with relatively scant diagnostic material without proper orientation which is usually retained in most of the surgical pathology specimens. These challenges are addressed if cell-blocks are prepared with some dedicated methodologies such as NextGen CelBloking™ (NGCB) kits. Cell-blocks prepared by NGCB kits also facilitate the easy application of the SCIP (subtractive coordinate immunoreactivity pattern) approach for proper evaluation of coordinate immunoreactivity. Various cell-block and IHC-related issues are discussed in detail.

Novel uses of immunohistochemistry in breast pathology: interpretation and pitfalls

Immunohistochemistry is an essential component of diagnostic breast pathology. The emergence of novel assays and applications is accompanied by new interpretation criteria and potential pitfalls. Immunohistochemistry assists in supporting breast origin for primary or metastatic carcinomas and identifying non-mammary metastases to the breast; however, no single immunostain is perfectly sensitive nor specific. GATA3 and Sox10 are particularly useful immunostains to identify triple negative breast carcinoma, which are often negative for other markers of mammary differentiation. Sox10 labeling is a major potential diagnostic pitfall, as Sox10 and S-100 label both triple negative breast carcinoma and metastatic melanoma; a pan-cytokeratin immunostain should always be included for this differential diagnosis. Novel immunohistochemistry serves as surrogates for the molecular alterations unique to several of special-type breast carcinomas, including the use of MYB in adenoid cystic carcinoma, pan-TRK in secretory carcinoma, and mutant IDH2 in tall cell carcinoma with reversed polarity (TCCRP). In addition, PD-L1 immunohistochemistry is an emerging, albeit imperfect, biomarker for breast cancer immunotherapy, with different assay parameters and scoring criteria in breast carcinoma compared to other tumor types. The expanding repertoire of novel immunohistochemistry provides additional diagnostic tools and biomarkers that improve diagnostic breast pathology and patient care.

CDX2, SATB2, GATA3, TTF1, and PAX8 Immunohistochemistry in Krukenberg Tumors

Twenty-six Krukenberg tumors (16 lower gastrointestinal, 4 upper gastrointestinal, and 6 of unknown origin) and their primaries when known were stained with CDX2, SATB2, GATA3, TTF1, and PAX8 using a tissue microarray containing predominantly or exclusively signet ring cells. The most common primary was appendiceal mixed adenoneuroendocrine carcinoma. CDX2 and SATB2 were positive in all known lower gastrointestinal primary tumors and negative in nearly all known upper gastrointestinal primary tumors. Primaries showed identical immunophenotypes to their metastases. Among cases of unknown primary origin, 3 were positive and 3 were negative for CDX2 and SATB2. Chest images, upper endoscopies, colonoscopies, appendectomies, and mammogram were performed with negative results in all, 4, 2, 2, and 1 cases, respectively. No cystoscopies were attempted. PAX8, GATA3, and TTF1 were negative in all cases. The literature was reviewed with emphasis on immunohistochemistry of signet ring cell-containing carcinomas from the appendix, colon, stomach, breast, lung, and bladder. Three quarters of gastric primaries stain for CDX2 and only rare examples stain for SATB2. Colorectal primaries (most of them) and appendiceal primaries (all of them) are positive for CDX2 and SATB2. GATA3 stains almost all breast primaries and approximately half of bladder primaries. All pulmonary primaries are positive for TTF1. PAX8 is negative in the gastric, colorectal, and appendiceal primaries reported. This study shows that the panel of immunostains is useful in confirming the site of origin of a metastatic Krukenberg tumor when one is known and has limited diagnostic value for diagnosing metastases of unknown origin.

NKX3-1 Is a Useful Immunohistochemical Marker of EWSR1-NFATC2 Sarcoma and Mesenchymal Chondrosarcoma

NK3 homeobox 1 (NKX3-1) is widely accepted as a highly sensitive and specific marker for prostatic adenocarcinoma. Prompted by published transcriptome data showing upregulation of NKX3-1 mRNA expression in EWSR1-NFATC2 sarcoma, we explored the utility of NKX3-1 immunohistochemistry in sarcoma diagnosis. We applied NKX3-1 immunohistochemistry to 11 EWSR1-NFATC2 sarcomas and 168 mimics using whole tissue sections. All EWSR1-NFATC2 sarcomas consisted of uniform small round or ovoid cells, all except 1 showing at least focally the typical growth pattern of nests, cords, or trabeculae within a fibrous/myxoid background. A variable eosinophilic infiltrate was common. NKX3-1 was expressed in 9 of 11 (82%) EWSR1-NFATC2 sarcomas, often diffuse and of moderate or strong intensity. All 12 mesenchymal chondrosarcomas tested were also positive for NKX3-1, with over half showing diffuse staining and moderate or strong intensity. The positive staining was seen only in the primitive small round cell component, whereas the cartilaginous component was mostly negative. Although 1 of 30 osteosarcomas showed focal NKX3-1 positivity, all the remaining 155 cases tested, including 20 Ewing sarcomas, 20 myoepithelial tumors, 11 ossifying fibromyxoid tumors, and 1 FUS-NFATC2 sarcoma were negative for NKX3-1. Our study provides the first evidence that EWSR1-NFATC2 sarcoma and Ewing sarcoma could be distinguished immunohistochemically, adding to the accumulating data that these tumors are phenotypically distinct. We suggest that NKX3-1 may have a diagnostic utility in the evaluation of sarcoma and we also call attention to potential pitfalls in the use of this well-known marker of prostatic adenocarcinoma.

PCSK2 expression in neuroendocrine tumors points to a midgut, pulmonary, or pheochromocytoma-paraganglioma origin

Neuroendocrine tumors (NETs) are often diagnosed from the metastases of an unknown primary tumor. Specific immunohistochemical (IHC) markers indicating the location of a primary tumor are needed. The proprotein convertase subtilisin/kexin type 2 (PCSK2) is found in normal neural and neuroendocrine cells, and known to express in NETs. We investigated the tissue microarray (TMA) of 86 primary tumors from 13 different organs and 9 metastatic NETs, including primary tumor‐metastasis pairs, for PCSK2 expression with polymer‐based IHC. PCSK2 was strongly positive in all small intestine and appendiceal NETs, the so‐called midgut NETs, in most pheochromocytomas and paragangliomas, and in some of the typical and atypical pulmonary carcinoid tumors. NETs showing strong positivity were re‐evaluated in larger tumor cohorts confirming the primary observation. In the metastases, the expression of PCSK2 mirrored that of the corresponding primary tumors. We found negative or weak staining in NETs from the thymus, gastric mucosa, pancreas, rectum, thyroid, and parathyroid. PCSK2 expression did not correlate with Ki‐67 in well‐differentiated NETs. Our data suggest that PCSK2 positivity can indicate the location of the primary tumor. Thus, PCSK2 could function in the IHC panel determined from screening metastatic NET biopsies of unknown primary origins.

PAX8 expression and TERT promoter mutations in the nested variant of urothelial carcinoma: a clinicopathologic study with immunohistochemical and molecular correlates

The nested variant of urothelial carcinoma, a frequent mimic of benign lesions on limited specimens, has been associated with high-stage disease including metastases at presentation. While PAX8 immunohistochemistry has been noted to be infrequently present in urothelial carcinoma in general, it has not been studied specifically in a cohort of nested urothelial carcinomas. Furthermore, TERT promoter mutation status is a potentially valuable biomarker for diagnosis of urothelial carcinoma and for noninvasive disease monitoring that has been observed in a majority of urothelial carcinoma and has previously been seen to be prevalent in multiple variant morphologies of urothelial carcinoma, including the nested variant. Twenty-five primary and three metastatic samples of nested urothelial carcinoma, along with 16 benign cases, were identified in a multicenter retrospective record review. PAX8 immunohistochemical stain was performed on all cases. In addition, TERT mutation analysis by allele-specific PCR was performed on 21 of the primary nested urothelial carcinoma cases and all benign cases. Positive PAX8 expression was identified in 52% (13 of 25) primary cases and 67% (2 of 3) metastatic cases of nested urothelial carcinoma; 50% (1 of 2) cases of large nested urothelial carcinoma were positive for PAX8. PAX8 expression was negative in the benign urothelium in all cases. TERT promoter mutation was observed in 83% (15 of 18) nested urothelial carcinoma cases and in 6% (1 of 16) of the benign cases. Recognition of the prevalence of positive PAX8 staining in this clinically relevant variant of urothelial carcinoma is essential to avoiding inaccurate or delayed diagnosis during the diagnostic workup of bladder lesions suspicious for nested variant of urothelial carcinoma. Moreover, the prevalence of TERT promoter mutations in nested urothelial carcinoma is similar to that of conventional urothelial carcinoma, further supporting its use as a biomarker that is stable across morphologic variants of urothelial carcinoma.

Cancer of Unknown Primary Site: Real Entity or Misdiagnosed Disease?

Metastasis is a late event in the progression of any tumour. However, invasive cancers are occasionally detected in the form of metastatic lesions without a clearly detectable primary tumour. Cancer of unknown primary site (CUP) is defined as a confirmed metastatic tumour, with unknown primary tumour site, despite the standardized diagnostic approach that includes clinical history, routine laboratory tests, and complete physical examination. Due to the lack of basic research on its primary causes, CUP is appropriately termed an 'orphan' cancer. Nevertheless, CUP accounts for 2-5% of diagnosed malignancies. To date, it is unclear whether CUP is an entity with primary dormancy as its hallmark or an entity with genetic abnormalities that cause it to manifest as a primary metastatic disease. In this review, we discuss different aspects of CUP, including its current diagnostic methods, angiogenesis effectors, relationship with cancer stem cells and current treatments.

Sclerosing Signet Ring Cell Carcinoma of the Lacrimal Gland: A Potentially New Primary Entity

An 88-year-old man presented with diplopia, limitation of extraocular movements, and a firm palpable mass in the superolateral orbit. Biopsy revealed a sclerosing signet ring cell carcinoma with histopathologic features mimicking those of a primary signet ring cell (histiocytoid) carcinoma of the eyelid of eccrine or apocrine gland origin, a metastasis from an invasive lobular breast carcinoma or a metastatic diffuse-type gastric carcinoma. An extensive panel of immunohistochemical stains and molecular genetic analyses unequivocally failed to establish a precise diagnosis. Electron microscopy demonstrated features of a primary lacrimal gland lesion with intracytoplasmic lumens and zymogen granules typical of lacrimal secretory pyramidal cells. A thorough initial systemic work-up failed to reveal a primary visceral malignancy. Fifteen months of follow-up have failed to detect the emergence of another primary malignancy. To the best of our knowledge, a tumor with the morphology of the current lesion has not been previously described in the major or accessory lacrimal glands.

A Review on Cancer of Unknown Primary Origin: The Role of Molecular Biomarkers in the Identification of Unknown Primary Origin

The primary site cannot be found after clinical and pathological evaluation, which are called cancers of unknown primary origin (CUP). CUPs may resemble a specific primary tumor site which shares common clinicopathological characteristics and prognosis. However, it may be present as a distinct disease entity with undifferentiated pathological features. More than 4% of patients are diagnosed as CUP. These patients were diagnosed as malignant tumors by cytology or pathology. And they were usually treated with empirical chemotherapy and associated with a poor prognosis. How to accurately diagnose and treat a cancer of unknown primary origin is a major clinical concern. To address this question, a complex assessment is carried out which includes a complete medical history of the patient, physical examination, complete blood count, urinalysis, serum chemistries, histologic evaluation, chest radiograph, computed tomography, magnetic resonance imaging, and immunohistochemistry (IHC) studies. Molecular diagnostic information reflects that CUP's molecular characteristics are similar to primary tumors with the development of genomics and the expansion of gene sequencing technology. Gene expression profiling is the most commonly used molecular diagnostic method for CUP. In this chapter, we summarize the current diagnostic methods and challenges of CUP, and the clinical value of the molecular-level tumor diagnostic technique.

Adenomyotic glands are highly related to endometrial glands

RESEARCH QUESTION

How closely related are adenomyotic and endometrial glands?

DESIGN

In this study, the mRNA and protein database www.proteinatlas.org was searched for proteins expressed predominantly in the endometrial glands. Specificity was tested with tissue microarrays. Biopsy specimens of endometrial, adenomyotic tissue, or both, were collected after surgery from 21 women without endometriosis, 20 women with endometriosis, 18 women with adenomyosis together with endometriosis and 12 women with adenomyosis alone. Tissue expression was analysed by immunohistochemistry.

RESULTS

Two proteins were identified: calcyphosine (CAPS), and msh homeobox 1 (MSX1). A high abundance and good specificity in endometrial glands were found. Both proteins, CAPS and MSX1, showed a high specificity for endometrium and are both localized in the luminal cells and epithelial cells of the glandular and adenomyotic glands. No significant differences were found between CAPS- and MSX1-positive endometrial glands between cases with and without endometriosis. Also, no cycle-specific different expression was found. Furthermore, a close relationship between the adenomyotic glands and the endometrial glands for CAPS (range 63.0-98.3%) and for MSX1 (range 87.1-99.3%) could be demonstrated. Only 11.2% and 6.8% negative glands for CAPS and MSX1 were identified in all tissues from all patients, respectively; none were negative for both proteins.

CONCLUSIONS

Taken together, our results show that the protein expression pattern of adenomyosis is nearly identical to those of the endometrium with and without endometriosis, thus suggesting endometrial glands as the main source for adenomyotic glands.

A practical guide for ancillary studies in pulmonary cytologic specimens

Although most pulmonary cytologic specimens obtained by either exfoliation or fine needle aspirates can be reliably and accurately diagnosed based on pure morphologic criteria alone, a small proportion of cases require ancillary studies for either refining a diagnosis, for resolving a differential diagnosis or increasingly, for predictive purposes in primary lung carcinomas. This article aims to provide practical guidance on the use of common ancillary studies in pulmonary cytologic specimens. Cancer Cytopathol 2018;000:000-000. © 2018 American Cancer Society.

Cancer of Unknown Primary: A Review on Clinical Guidelines in the Development and Targeted Management of Patients with the Unknown Primary Site

Cancer of unknown primary (CUP) is a malignant widespread metastatic disease without an identifiable primary site after extensive clinical investigation. Recently, a decline is observed in the diagnosis of CUP, mainly due to improvement in detection of the primary tumors, thus decreasing the unknown primaries. Worldwide, CUP is the sixth to eighth most common malignancy, accounting for 2.3% to 5% of a new cancer diagnosis. CUP is third to fourth most common cause of death due to cancer-related mortality. The prognosis of CUP is depressing with the median survival of three to six months in the previous studies, but according to recent studies, median survival is less than one year. High risk for developing CUP is seen in heavy smokers (26 or more cigarettes/day) and individuals with the lowest quartiles of waist circumference. A weak association is observed with the use of alcohol consumption and low level of education. Human papillomavirus DNA plays a role in those with squamous cell carcinoma of unknown primaries in head and neck regions. In the diagnosis of CUP, comprehensive medical history, complete physical examination (including genitourinary, rectal exam, and breast examination in women) and necessary laboratory tests are crucial.

Whole-body positron emission tomography-computed tomography (PET/CT) is the investigation of choice to assess the entire body for CUP. Multiparametric 3T-MRI (MP-MRI) is used to examine the local soft tissue status, helps in the staging of the tumor, and to determine the extent of involvement of tissue for medical as well as prognostic purposes. Immunohistochemistry outlines the specific markers, including caudal-related homeobox protein (CDX2), homeobox protein Nkx-3.1 (NKX3-1), paired box gene 8 (PAX8), special AT-rich sequence-binding protein 2 (SATB2), thyroid transcription factor 1 (TTF-1), and splicing factor 1 (SF1) with the focus on the effectiveness of lineage-restricted transcription factors. Patients response to treatment can be evaluated by the gene expression profiling (GEP) test that also predicts tissue of origin (TOO). Tumor identified through gene profiling is sensitive to platinum/taxane therapy, others that are not TOO tumors are resistant to platinum/taxane. The new therapeutic method based on molecular profiling is associated with higher treatment response. In comprehensive genomic profiling, it is observed that there is at least one clinically appropriate genomic alteration in CUP that can influence the targeted therapy. The targeted therapeutic approach will not only improve the disease outcome but will also be cost-effective and save time from finding the primary site.

Practical Application of Lineage-Specific Immunohistochemistry Markers: Transcription Factors (Sometimes) Behaving Badly

CONTEXT.—

Transcription factors (TFs) are proteins that regulate gene expression and control RNA transcription from DNA. Lineage-specific TFs have increasingly been used by pathologists to determine tumor lineage, especially in the setting of metastatic tumors of unknown primary, among other uses. With experience gathered from its daily application and increasing pitfalls reported from immunohistochemical studies, these often-touted highly specific TFs are not as reliable as once thought.

OBJECTIVES.—

To summarize the established roles of many of the commonly used TFs in clinical practice and to discuss known and potential sources for error (eg, false-positivity from cross-reactivity, aberrant, and overlap "lineage-specific" expression) in their application and interpretation.

DATA SOURCES.—

Literature review and the authors' personal practice experience were used. Several examples selected from the University Health Network (Toronto, Ontario, Canada) are illustrated.

CONCLUSIONS.—

The application of TF diagnostic immunohistochemistry has enabled pathologists to better assess the lineage/origin of primary and metastatic tumors. However, the awareness of potential pitfalls is essential to avoid misdiagnosis.

[Carcinoma with unknown primary site: Morphological diagnosis]

Carcinoma with unknown primary site (CUPs) is a group of malignant tumors, the first manifestation of which is metastatic dissemination. A primary tumor cannot be usually identified by a physical examination of patients with CUPs; a postmortem study plays a significant role in the diagnosis of the origin of metastasis. The paper gives the data available in the literature data on the postmortem diagnosis of CUPs and considers the morphological characteristics of metastases and the possibilities of immunohistochemical diagnosis and a molecular genetic method in the search for a primary focus.