Diagnostic utility of CDX-2 expression in separating metastatic gastrointestinal adenocarcinoma from other metastatic adenocarcinoma in fine-needle aspiration cytology using cell blocks

Sialendoscopic removal of metastatic adenocarcinoma in a mucous plug from Stensen's duct

Sialendoscopy is a minimally invasive technique used mainly in the diagnosis and treatment of obstructive salivary gland disorders. There has yet to be a report on its use in the diagnosis of metastatic disease. While metastatic cancer has been described in numerous head and neck anatomic subsites, it has not been reported to be found in a mucous plug in Stensen's duct. Sialendoscopy was performed in a 68-year-old female patient who presented with symptoms of ductal obstruction. Basket removal of a mucous plug was done and histopathological analysis of this specimen found adenocarcinoma. The overall clinical picture, imaging, and final histopathological results suggested that this patient had metastatic breast carcinoma to a mucous plug in Stensen's duct, the diagnosis of which was made with the aid of interventional sialendoscopy. This is the first report in which metastatic cancer was identified in a mucous plug in Stensen's duct. Sialendoscopy can be a useful tool to aid in the diagnosis of metastatic diseases in rare and unusual clinical situations.

Evaluation of Carcinoma of Unknown Primary on Cytologic Specimens

Carcinoma of unknown primary is defined as metastatic carcinoma without a clinically obvious primary tumor. Determining the tissue of origin in carcinoma of unknown primary is important for site-directed therapy. Immunohistochemistry is the most widely used tool for the work-up of metastases, but molecular profiling assays are also available. This review provides an overview of immunohistochemical stains in the work-up of metastatic carcinoma, with a focus on newer site-specific markers, and discusses the role of gene expression profiling assays for determining tissue of origin. The utility of cytopathology specimens in the evaluation of carcinoma of unknown primary also is highlighted.

Pathology of Liver Metastases

BACKGROUND

The liver is the most frequent site of metastatic disease, and metastatic disease to the liver is far more common than primary liver carcinoma in the United States. Pathologic evaluation of biopsy samples is key to establishing a correct diagnosis for patient management. Morphologic and immunoperoxidase studies, which are the standard for pathologic practice, accurately classify most tumors. Subclassification of carcinoma of unknown primary remains problematic.

METHODS

The author reviewed the literature for articles pertaining to liver biopsy, diagnosis of specific tumor types, utility of immunohistochemical markers, and microarray and proteomic analysis.

RESULTS

Sampling of liver lesions is best accomplished by combining fine-needle aspiration and needle core biopsy. Many malignancies have distinct morphologic and immunohistochemical patterns and can be correctly subclassified. Adenocarcinoma of unknown primary remains enigmatic since current immunohistochemical markers for this differential diagnosis lack specificity. Microarray analysis and proteomic analysis of tumors can provide distinct gene or protein expression profiles, respectively, for tumor classification. These technologies can be used with fine-needle aspiration and needle core biopsy samples.

CONCLUSIONS

Most metastatic malignancies in the liver may be correctly diagnosed using standard morphology and immunohistochemical techniques. However, subtyping of some carcinomas and identification of site of unknown primary remains problematic. New technologies may help to further refine our diagnostic capabilities.

Primary pancreatic-type acinar cell carcinoma of the jejunum with tumor thrombus extending into the mesenteric venous system: a case report and literature review

BACKGROUND

Although ectopic pancreatic tissue is common in the upper gastrointestinal tract, the incidence of ectopic pancreatic tissue in the jejunum is low, and malignant transformation in ectopic pancreatic tissue is rare. Furthermore, pancreatic-type acinar cell carcinoma (ACC) developing in the jejunum and ACC accompanied by tumor thrombus are extremely rare.

CASE PRESENTATION

A 78-year-old-woman presented with melena. Abdominal computed tomography images and endoscopic examination revealed a submucosal jejunal mass with tumor thrombus extending into a jejunal vein. The patient underwent a curative resection combined with a partial jejunectomy and partial pancreatectomy. Histopathological examination of the resected tissue showed tumor cells with a homogeneous acinar architecture identical to pancreatic-type ACC and tumor thrombus. Postoperatively, she was followed for 10 months and had no recurrence.

CONCLUSION

We present an extremely rare case of pancreatic-type ACC in the jejunum with extensive tumor thrombus invading into the mesenteric venous system. This type of cancer has not been reported previously but should be considered in the differential diagnosis of a jejunal mass.

Adenocarcinoma arising from jejunal ectopic pancreas mimicking peritoneal metastasis from colon cancer: a case report and literature review

Adenocarcinoma arising from jejunal ectopic pancreas is very rare. We report a case of a 69-year-old female with adenocarcinoma arising from jejunal ectopic pancreas after resection of advanced colon cancer. She underwent right hemicolectomy for advanced ascending colon cancer (ypT3N0M0, stage IIA) after chemotherapy. Two and half years after colectomy, her tumor markers were elevated, and computed tomography revealed a mass measuring 20 × 20 mm in the small intestine, having an abnormal uptake of ¹⁸F-fluorodeoxyglucose on ¹⁸F-fluorodeoxyglucose-positron emission tomography (¹⁸FDG-PET). Double-balloon enteroscopy revealed a submucosal tumor in the jejunum, and histopathology of biopsy specimens from that lesion showed ectopic pancreas without malignancy. Therefore, peritoneal metastasis from colon cancer concomitant with ectopic pancreas or adenocarcinoma arising from ectopic pancreas was considered as a differential diagnosis. She underwent laparoscopic jejunectomy. Pathological examination revealed a moderately differentiated adenocarcinoma arising from jejunal ectopic pancreas, not peritoneal metastasis from colon cancer. Even if histopathology of the biopsy specimen shows ectopic pancreas without malignancy, adenocarcinoma arising from ectopic pancreas should be considered when the tumor markers are elevated or the lesion has an abnormal uptake of ¹⁸FDG.

Steatocystoma multiplex as initial impression of non-small cell lung cancer with complete response to gefitinib

Cutaneous metastases are rare and seldom present at the time of first diagnosis of cancer. Data from various studies show that 1-12% of lung cancer patients experience tumor spread to the skin. The scalp, chest, and abdomen are favored sites of skin metastases from lung cancers, but metastases to multiple skin sites in a single patient are rarely reported. We describe a 56-year-old lung adenocarcinoma patient, initially diagnosed with steatocystoma multiplex who responded well to gefitinib treatment. The efficacy of conventional chemotherapy for cutaneous metastases has been limited because of the relatively poor blood supply to the skin. It has been demonstrated that tyrosine kinase inhibitor (TKI), gefitinib, has significant clinical benefit in lung cancer patients with epidermal growth factor receptor (EGFR) mutation even in metastases to the brain. However, the therapeutic response to gefitinib in patients with skin metastases is seldom mentioned in the literature. We report one case of lung adenocarcinoma with multiple skin metastases that were successfully treated with gefitinib.

Immunohistochemistry of colorectal carcinoma: current practice and evolving applications

The relatively high incidence of adenocarcinoma of the colon and rectum (colorectal carcinoma) in the general population makes its pathologic diagnosis one of the more frequent exercises in anatomical pathology. Although typically mundane in the primary setting, the correct identification of metastatic colorectal carcinoma or exclusion of metastatic disease from carcinoma arising in other anatomical foci can be problematic. The advent of targeted therapies and refinement of more traditional cytotoxic chemotherapeutic regimens mandates not only a more confident appraisal of site of origin but also assessment of those tumor-specific features that may alter therapeutic decisions. Despite the exponential increase in our understanding of the molecular pathogenesis of colorectal carcinoma, immunohistochemistry remains the foundation for resolution of these problematic cases and the number of antibodies available to the practicing pathologist continues to expand at a steady rate. In some cases, immunohistochemistry may also provide valuable prognostic information, either independently or as a surrogate marker for a specific route of carcinogenesis such as microsatellite instability. This review will focus on the use of new and more established immunohistochemistry markers in the diagnosis of colorectal carcinoma, with an emphasis on aberrant staining patterns of the various colorectal carcinoma subtypes as well as the utility of these markers in specific differential diagnostic settings.

CDX2 as a marker for intestinal differentiation: Its utility and limitations

CDX2 is a nuclear homeobox transcription factor that belongs to the caudal-related family of CDX homeobox genes. The gene encoding CDX2 is a nonclustered hexapeptide located on chromosome 13q12-13. Homeobox genes play an essential role in the control of normal embryonic development. CDX2 is crucial for axial patterning of the alimentary tract during embryonic development and is involved in the processes of intestinal cell proliferation, differentiation, adhesion, and apoptosis. It is considered specific for enterocytes and has been used for the diagnosis of primary and metastatic colorectal adenocarcinoma. CDX2 expression has been reported to be organ specific and is normally expressed throughout embryonic and postnatal life within the nuclei of epithelial cells of the alimentary tract from the proximal duodenum to the distal rectum. In this review, the authors elaborate on the diagnostic utility of CDX2 in gastrointestinal tumors and other neoplasms with intestinal differentiation. Limitations with its use as the sole predictor of a gastrointestinal origin of metastatic carcinomas are also discussed.

Metastasis of colon cancer to the thyroid gland: a case diagnosed on fine-needle aspirate by a combined cytological, immunocytochemical, and molecular approach

Fine-needle aspiration (FNA) with cytological evaluation reliably diagnoses primary and secondary thyroid neoplasms. However, identifying the primary origin of a metastatic process involving the thyroid gland is challenging. In particular, metastasis of colon cancer to the thyroid gland is very rare. In this case report, a right lobe solid thyroid nodule in a 66-year-old male was aspirated. FNA cytology showed necrosis and atypical tall columnar cells; since, the patient at age 60 had undergone surgery for a sigmoid-rectal cancer metastasizing to the liver and subsequently to the lung, a suspicion of metastasis from colon cancer was raised. This was corroborated by cell-block immunocytochemistry showing a cytokeratin (CK) 7 negative/CK20-positive staining pattern; thyreoglobulin and TTF-1 were both negative. Since KRAS codon 12/13 mutations frequently occur in colon cancer, whereas they are extremely uncommon in primary thyroid tumors, DNA was extracted from the aspirated cells, and KRAS mutational analysis was carried out. The codon 12 G12D mutation was found; the same mutation was evident in the primary cancer of the colon and in its liver and lung metastasis. Thus, a combined cytological, immunocytochemical and molecular approach unquestionably correlated metastatic adenocarcinoma cells aspirated from the thyroid to a colo-rectal origin.

Double primary adenocarcinomas of the jejunum and descending colon with lung metastases presenting rare immunohistochemical phenotypes: a case report

We report a male patient with double advanced tumors in the jejunum and descending colon and multiple lung tumors. The intestinal cancers were surgically resected. Immunoprofiling of the specimens revealed a rare phenotype: the jejunal cancer was positive for cytokeratin (CK) 7, partially positive for CK20, and Cdx-2-negative, whereas the colon cancer was CK7(+), CK20(-), and Cdx-2(-). Biopsied lung tumor was diagnosed as tubular adenocarcinoma, and CK7(+)/CK20(+)/Cdx-2(-). Together with clinical information, we deduced that the jejunal adenocarcinoma had presumably metastasized to the lung. Moreover, postoperative oxaliplatin, including chemotherapy, significantly reduced the lung metastases, suggesting that this regimen is a promising treatment option for advanced small bowel adenocarcinoma.

CDX-2 expression is a common event in primary intestinal-type endocervical adenocarcinoma

We studied the expression of cytokeratin (CK) 7, CK20, CDX-2, and p16 in 119 cervical adenocarcinomas (65 usual type [50 invasive; 15 in situ], 37 intestinal type [21 invasive; 16 in situ], 10 endometrioid, 5 adenosquamous, and 2 signet-ring carcinomas) in comparison with 55 cases of rectal adenocarcinomas. The percentage of cells staining was considered negative if 0% to 5% stained; more than 5% was considered positive. For p16, staining of more than 50% was considered positive. CK7 was expressed in all cervical cases and in 12 rectal adenocarcinomas (22%). CK20 was expressed in 17 cervical adenocarcinomas (14.3%) and in 48 rectal adenocarcinomas (87%). CK20 immunostaining was diffuse in the majority of rectal tumors but focal in most cervical tumors. CDX-2 was expressed in all cases of rectal adenocarcinoma and in 46 cervical adenocarcinomas (38.7%): usual type, 10 (15%); intestinal type, 31 (84%); endometrioid type, 5 (50%); adenosquamous and signet-ring types, 0 (0%). CDX-2 is a marker for intestinal differentiation irrespective of a rectal or cervical origin. Therefore, it should not be used as the sole basis to confirm the colorectum as the primary origin in metastatic cases.

Merkel cell carcinoma of the inguinal lymph node with an unknown primary site

Merkel cell carcinoma (MCC) is an uncommon and aggressive primary neuroendocrine malignancy of the skin. Frequent local recurrences and disseminations to regional lymph nodes and distant organs are characteristic. MCC within the lymph nodes in the absence of a primary site is rare and has only been reported sporadically. We report a case of MCC presenting as a painless mass in the left inguinal area for 5 months in a 57-year-old man. The histopathology of the excised lesion revealed a poorly differentiated basophilic small cell tumor. The tumor cells were positive for cytokeratin 20 and CD56, negative for cytokeratin 7, thyroid transcription factor-1 and CDX-2. These immunohistochemical findings were consistent with the diagnosis of a metastatic MCC. Despite extensive clinical and radiological investigation, we failed to identify the origin of the tumor. Our case may represent a lymph node metastasis from an occult or regressed skin primary, but we cannot preclude the possibility of a primary nodal tumor.

CDX2, cytokeratins 7 and 20 immunoreactivity in rectal adenocarcinoma

There are limited data regarding CDX2 expression in rectal carcinoma. The CK20/CK7 immunoprofile of colorectal adenocarcinoma has been described in studies, which have mostly lumped colonic and rectal tumors together. In this study, we investigated the diagnostic utility of immunohistochemical stains for CK7, CK20, and CDX2 in a series of rectal adenocarcinoma. Fifty-five specimens of rectal adenocarcinomas were retrieved and immunostained for CK7 (Dako-M7018), CK20 (NovoCastra NCL-L-CK20), and CDX2 (NovoCastra NCL-CDX2). Thirty cases of pancreatic adenocarcinoma and 15 cholangiocarcinomas were also studied as a comparison group. CK7 was expressed in 12/55 (22%) and CK20 in 48/55 (87%) cases of rectal adenocarcinoma. The CK7-/CK20+ immunophenotype was identified in 36/55 (65%), CK7+/CK20+ in 12/55 (22%), and CK7-/CK20- in 7/55 (13%) rectal adenocarcinoma. CDX2 showed moderate-strong positivity in all cases and was not related to tumor differentiation. Benign rectal mucosa was available in 37 cases and showed the following results: CK7-/CK20+ in 25/37 (67%), CK7+/CK20+ in 8/37 (22%) and CK7-/CK20- in 4/37 (11%) cases. In pancreatic adenocarcinomas and cholangiocarcinomas, 29/45 (64%) were CK7+/CK20+ and 16/45 (36%) were CK7+/CK20-. CDX2 was positive in only 3/45 (7%) of these cases; all were pancreatic adenocarcinomas. In conclusion, CK7 can be expressed in rectal adenocarcinoma, and should not be used as the sole basis for excluding a rectal primary. CDX2 is a sensitive marker for rectal origin of adenocarcinoma. It can be helpful in cases with metastatic rectal carcinoma, especially those with CK7+/CK20+ or CK20-/CK7- immunophenotype. In this study, CDX2 expression was not influenced by the grade (differentiation) of rectal adenocarcinoma.

Utility of tissue-specific transcription factors thyroid transcription factor 1 and Cdx2 in determining the primary site of metastatic adenocarcinomas to the brain

CONTEXT

Brain metastases of adenocarcinoma of unknown primary pose a diagnostic dilemma to the surgical pathologist. Although the most common source in these cases is the lung, determining a primary source is difficult on routinely stained slides. Immunohistochemical stain panels including differential cytokeratins, hormone receptors, and breast-specific proteins are commonly used in these cases. Recently, attention has turned to tissue-specific transcription factors, such as thyroid transcription factor 1 (TTF-1) and Cdx2, in the appraisal of metastatic adenocarcinomas.

OBJECTIVE

To characterize the previously unpublished immunohistochemical expression of the relatively new tissue-specific transcription factor Cdx2 in metastatic adenocarcinomas to the brain.

DESIGN

We reviewed the surgical pathology files of the H. Lee Moffitt Cancer Center and Research Institute, Tampa, Fla, and retrieved 38 consecutive cases of metastatic adenocarcinoma (22 pulmonary, 10 breast, 6 gastrointestinal [2 esophagus/gastroesophageal junction, 4 colorectal]) to the brain with confirmation of the primary site by chart review and histologic evaluation. Sections were immunohistochemically stained with antibodies to TTF-1, Cdx2, and cytokeratins 7 and 20 by standard methods.

RESULTS

Specificities and positive predictive values for Cdx2 and TTF-1 equaled 100% for metastatic gastrointestinal and pulmonary adenocarcinomas, respectively. The negative predictive value of Cdx2 was also very high at 97%.

CONCLUSIONS

Cdx2 is a specific and valuable tool for the surgical pathologist when faced with the common problem of metastatic adenocarcinoma of unknown primary. In conjunction with TTF-1, cytokeratin 7, and cytokeratin 20, Cdx2 can accurately differentiate the most common sources of metastatic adenocarcinoma to the brain.

The diagnosis of malignancy in effusion cytology: a pattern recognition approach

This review presents a pattern recognition approach for the diagnosis of malignant effusions. The cytomorphologic features of reactive mesothelial proliferation, mesothelioma and metastatic carcinoma are presented. In addition, the role of ancillary studies in challenging cases and the importance of integrating clinical findings are stressed. An algorithmic approach to the workup of serous effusions as well as pitfalls for false-positive diagnosis are discussed.

CDX-2 expression in pulmonary fine-needle aspiration specimens: a useful adjunct for the diagnosis of metastatic colorectal adenocarcinoma

CDX-2 is a homeobox gene, which encodes a transcription factor that plays a vital role in the development and differentiation of intestinal epithelial cells. Recent studies showed that CDX-2 protein expression by immunohistochemistry (IHC) has a high predictive value for confirming the diagnosis of colorectal adenocarcinoma (ACA). The differentiation of primary pulmonary ACA from metastatic colorectal ACA can be extremely challenging on fine-needle aspiration (FNA). The results of immunostains for TTF-1, CK 7, and CK 20 may be controversial in the differential diagnosis. In this study, we evaluated the clinical utility of CDX-2 in lung FNA specimens. Cell blocks from 41 primary lung and 20 colorectal ACAs metastatic to the lungs were retrieved. Cell block sections were immunostained with a CDX-2 monoclonal antibody. Sensitivity and specificity of CDX-2 for colorectal ACA was 75 and 100%, respectively. All five cases negative for CDX-2 were moderately to poorly differentiated colorectal ACAs. Our study confirms that CDX-2 is a highly useful immunohistochemical marker for the differentiation of primary pulmonary ACA from colorectal ACA metastatic to the lungs in FNA specimens. Of diagnostic importance is the loss of CDX-2 immunoreactivity in poorly differentiated colorectal ACAs.