Morphology and Molecular Features of Rare Colorectal Carcinoma Histotypes

Several histopathological variants of colorectal carcinoma can be distinguished, some associated with specific molecular profiles. However, in routine practice, ninety/ninety-five percent of all large bowel tumors are diagnosed as conventional adenocarcinoma, even though they are a heterogeneous group including rare histotypes, which are often under-recognized. Indeed, colorectal cancer exhibits differences in incidence, location of tumor, pathogenesis, molecular pathways and outcome depending on histotype. The aim is therefore to review the morphological and molecular features of these rare variants of intestinal carcinomas which may hold the key to differences in prognosis and treatment.

The Relationship Between E-Cadherin and its Transcriptional Repressors in Spontaneously Arising Canine Invasive Micropapillary Mammary Carcinoma

E-cadherin downregulation is related to metastatic behaviour and a poor prognosis in cancer. It might be induced by transcriptional repression mediated by the transcription factors SNAIL, ZEB1, ZEB2 and TWIST. Here, we investigated E-cadherin expression and its relationship to those transcriptional repressors (i.e. SNAIL, ZEB1, ZEB2 and TWIST) in the progression from carcinoma 'in situ' to invasion to lymph node metastasis in spontaneously arising canine invasive micropapillary carcinoma (IMPC). E-cadherin expression decreased from carcinoma in situ to invasive progression and was likely to increase with lymph node metastasis. Expression of SNAIL decreased from carcinoma in situ to invasive areas and from invasive areas to lymph nodes. Metastatic lymph nodes had higher expression of ZEB1 than carcinoma in situ and invasive areas. ZEB2 expression was observed in 52%, 38% and 33% of carcinoma in situ areas, invasive areas and lymph node metastases, respectively. TWIST expression was observed in 52%, 38% and 33% of carcinoma in situ areas, invasive areas and lymph node metastases, respectively. In invasive areas, E-cadherin downregulation correlated significantly with SNAIL and TWIST upregulation. Additionally, in infiltrating components of IMPCs, E-cadherin(-)SNAIL(+) neoplastic epithelial cells were observed by immunofluorescence. Taken together, canine mammary IMPCs had a loss of E-cadherin from carcinoma in situ to invasive areas, which appears to be induced by the transcription factor SNAIL. In lymph node metastasis, ZEB1 appears to not exert E-cadherin transcriptional repression activity.

Aberrant activation of Rho/ROCK signaling in impaired polarity switching of colorectal micropapillary carcinoma

Micropapillary carcinoma (MPC) is a morphologically distinctive form of carcinoma, composed of small nests of cancer cells surrounded by lacunar spaces. Invasive MPC is associated with poor prognosis. The nests of tumor cells in MPC reportedly exhibit reverse polarity, although the molecular mechanisms underlying MPC patterns are poorly understood. Using the cancer tissue-originated spheroid (CTOS) method, we previously reported polarity switching in colorectal cancer (CRC). When cultured in suspension, the apical membrane promptly switches from the outside surface of the CTOSs to the surface of the lumen inside the CTOSs under extracellular matrix (ECM)-embedded conditions, and vice versa. Here, we investigated two CTOS lines from CRC patient tumors with MPC lesions. Xenograft tumors from the CTOSs exhibited the MPC phenotype. The MPC-CTOSs did not switch polarity in vitro. Time-course analysis of polarity switching using real-time imaging of the apical membrane revealed that local switching was continually propagated in non-MPC-CTOSs, while MPC-CTOSs were unable to complete the process. Integrin β4 translocated to the outer membrane when embedded in ECM in both MPC and non-MPC-CTOSs. Protein levels, as well as the active form of RhoA, were higher in MPC-CTOSs. The suppression of RhoA activity by GAP overexpression enabled MPC-CTOSs to complete polarity switching both in vitro and in vivo, while overexpression of active RhoA did not affect polarity switching in non-MPC-CTOSs. Pretreatment with a ROCK inhibitor enabled MPC-CTOSs to complete polarity switching both in vitro and in vivo, although delayed treatment after becoming embedded in ECM failed to do so. Thus, the inability to switch polarity might be a cause of MPC, in which the aberrant activation of RhoA plays a critical role. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Is age associated with risk of malignancy in thyroid cancer?

OBJECTIVES

Many predictive models for risk of malignancy in well-differentiated thyroid cancer (WDTC) have been proposed, and many scoring systems for thyroid cancer prognosis have been established. Age is taken in consideration in all. Our main goal is to establish whether patients' age has a correlation with the rate of malignancy, size, and aggressiveness of the tumor.

STUDY DESIGN

Case series with chart review.

SETTING

McGill University Thyroid Teaching Hospitals.

SUBJECTS AND METHODS

A retrospective analysis of 1022 patients undergoing consecutive thyroidectomy was performed. The patients were divided based on age (<45 and ≥ 45 years). Data were gathered for the size of thyroid nodules, the presence of lymph node (LN) metastasis, and the final thyroid pathology, including the presence of extrathyroidal extension.

RESULTS

There were 396 patients younger than 45 years and 626 patients 45 years or older. The rates of malignancy were 67.2% in the first group and 68.7% in the second group (P = .111). When patients were stratified according to different age cutoffs, WDTC and LN metastasis occurred more often in patients younger than 50 years (50.2% vs 43.2%, P = .031 and 18.9% vs 14.1%, P = .0496, respectively). Micropapillary carcinoma occurred more often in patients 50 years or older (23.6% vs 16.1%, P = .0035).

CONCLUSIONS

Tumor behavior and rates of WDTC were similar in patients aged <45 and ≥ 45 years. Well-differentiated thyroid cancer occurred more often in patients younger than 50 years, whereas the rate of micropapillary carcinoma occurred more often in patients 50 years or older.

The Impact of Micropapillary Component Ratio on the Prognosis of Patients With Invasive Micropapillary Breast Carcinoma

Background and Objectives: Invasive micropapillary carcinoma (IMPC) of the breast is a rare and aggressive variant of invasive ductal carcinoma characterized by high-grade lymphovascular invasion and high rates of nodal metastasis. The prognostic significance of the micropapillary component (MC) ratio that constitutes this aggressive variation is controversial. In this study, we aimed to investigate the effect of the MC ratio on the prognosis of these patients. Methods: The data of 47 patients with IMPC were retrospectively reviewed. Patients were divided into two groups: MC ratio of 10-75% (Group 1) and greater than 75% (Group 2). The demographic characteristics of the patients, histopathologic features of the tumors, and survival rates were compared. Results: We detected no significant difference in demographic characteristics between groups 1 and 2 (p = 0.21). No significant difference was detected in terms of tumor diameter, lymph node metastasis, lymphovascular invasion, histologic grade, multicentricity, local recurrence, distant metastasis, and overall survival. Conclusion: In the micropapillary subgroup of invasive ductal carcinoma, although positive receptor characteristics are directly proportional to the increase in MC ratio, recurrence and survival rates are not affected by micropapillary component level.

Solitary Gastric Metastasis from a Stage IA Serous Ovarian Carcinoma: A Case Report with Literature Review

Gastric metastasis from ovarian cancer is exceptionally rare and generally occurs in advanced stages. A 71-year-old woman presented with a solitary gastric submucosal mass 8 years after the diagnosis of a stage IA ovarian serous adenocarcinoma. Endoscopy showed a tumor covered with normal gastric mucosa. Initially, a gastrointestinal stromal tumor was suspected, but biopsy revealed a histology of invasive micropapillary carcinoma, similar to the histological findings of the previously resected ovarian tumor. Clinicians should consider that in patients with a submucosal tumor and a history of ovarian cancer, gastric lesions may be secondary metastases from ovarian cancer.

Cytological features of pure micropapillary carcinoma of various organs: A report of eight cases

Micropapillary carcinoma (MPC) is a rare aggressive tumor, which generally accompanies the primary carcinoma of the organ of its origin, while the pure form is extremely uncommon. Angiolymphatic involvement is widespread and a considerable proportion of the cases present with metastases. The current study presents eight pure MPC cases arising from the breast (n=3), urinary bladder (n=3), parotid gland (n=1) and lung (n=1, presenting with pericardial effusion), with the cytological findings. The eight patients included three female and five male cases aged between 48 and 74 years. The most common cytological findings were three-dimensional aggregates, cell clusters with angulated or scalloped borders, single cells with a columnar configuration and eccentric nuclei, and high-grade nuclear features. Histopathological sections showed accompanying in situ ductal carcinoma in the cases of MPC arising in the parotid gland and breast (n=3), and one case in the bladder exhibited only in situ MPC. The average follow-up period was 20 months (range, 6–54 months) and, during this period, three patients succumbed to the disease. At present, four patients are alive with disease and one patient is alive and disease-free. In conclusion, cytology is an important tool for the diagnosis and management of MPC.

The Expression of Galectin-3 in Tumor and Cancer-Associated Fibroblasts in Invasive Micropapillary Breast Carcinomas: Relationship with Clinicopathologic Parameters

Objective

Galectin-3 affects tumor progression and cell surface polarization by expressing from the tumor and cancer-associated fibroblasts (CAFs). Therefore, it may have a role on micropapillary carcinomas (IMPC), which have characteristic morphological features. The aim was to investigate the expression levels of Galectin-3 within tumor and peritumoral CAFs in IMPC, and to compare with expression in invasive ductal carcinomas (IDC).

Materials and Methods

Hematoxylin and Eosin-stained preparations of resection materials examined between 2010-2016 were re-evaluated. Thirty-four IMPC cases and 34 IDC cases with similar molecular subtype distribution to IMPC were compared. Galectin-3 levels were evaluated with a calculated H-score in tumor and semi-quantitatively in CAFs.

Results

While tumoral Galectin-3 expression levels were higher in IMPCs compared to IDCs, there was no difference for Galectin-3 expression in CAFs between the two histologic types. However, there was no significant relationship between tumoral Galectin-3 expression and clinicopathological parameters in IMPCs. When the subjects were divided into two groups, depending on their Galectin-3 status regardless of histological types, the loss of Galectin-3 expression in tumor was found to be related to larger tumor size/advanced pT stage and a greater number of metastatic nodes. Additionally, expression of Galectin-3 in CAFs was found to be associated with distant metastasis.

Conclusion

IMPC showed prominent Galectin-3 expression in tumor compared to IDC. However, independent from the histological type, whereas the loss of Galectin-3 expression in tumor showed an association with larger tumor size and higher number of metastatic axillary lymph nodes, the presence of Galectin-3 expression in CAFs showed an association with distant metastasis.

[Invasive micropapillary carcinoma: a rare and aggressive breast cancer]

Invasive micropapillary carcinoma of the breast is a rare and distinct histological variant of breast cancers, accounting for less than 3% of all breast carcinomas. It is characterized by a pejorative prognosis due to heavy lymph node involvement and the presence of numerous vascular and lymphatic emboli. We here report the case of a 63-year-old woman presenting with left mastodynia evolving for two months. Physical examination revealed breast asymmetry with skin retraction and multiple suspected lymph nodes in the left axilla. Mammography objectified a spiculated mass in the left breast classified as ACR5. Breast microbiopsy showed invasive micropapillary carcinoma. The patient underwent left Patey’s mastectomy with ipsilateral axillary dissection. Macroscopically, the tumor was grayish-white with spiculated margins located at the union of the two external quadrants and measuring 13 x 8 cm (Panel A). Histological examination of the surgical specimen revealed invasive carcinomatous proliferation arranged in clusters, nests, micropapillae, morules and glands with reversed polarity within a fibro-inflammatory stroma retracted around the carcinomatous structures (Panel B, C). Histoprognostic grading (SBR grade) modified according to ELSTON and ELLIS was 3. Several peritumoral vascular emboli were detected as well as lymph nodes metastases 20N+/20N. Immunohistochemistry using EMA showed reversed polarity (Figure D). Molecular classification of the tumor was luminal B. The postoperative course was simple. The patient underwent adjuvant chemoradiotherapy. Currently, the patient is systematically monitored on an outpatient basis.

Abnormality of Apico-Basal Polarity in Adenocarcinoma

Apico–basal polarity is a fundamental property of the epithelium that functions as a barrier, holds cells together, and determines the directions of absorption and secretion. Apico–basal polarity is regulated by extracellular matrix‐integrin binding and downstream signaling pathways, including focal adhesion kinase, rouse‐sarcoma oncogene (SRC), and RHO/RHO‐associated kinase (ROCK). Loss of epithelial cell polarity plays a critical role in the progression of cancer cells. However, in differentiated carcinomas, polarity is not completely lost but dysregulated. Recent progress with a three‐dimensional culture of primary cancer cells allowed for studies of the mechanism underlying the abnormality of polarity in differentiated cancers, including flexible switching of polarity status in response to the microenvironment. Invasive micropapillary carcinoma (MPC) is one of the histopathological phenotypes of adenocarcinoma, which is characterized by inverted polarity. Aberrant activation of RHO–ROCK signaling plays a critical role in the MPC phenotype. Establishing in vitro models will contribute to future drug targeting of the abnormal polarity status in cancer.

Micropapillary structure: A natural tumor collective invasion model with enhanced stem-like properties

Cancer stem cells aggregate to form clusters, which have enhanced stem-like properties and metastasis potential. However, the molecular mechanisms underlying the formation of cancer stem cell cluster-like structures with acquisition of stronger invasion and metastasis abilities remain unclear. Micropapillary carcinoma (MPC) is a subpopulation of small, merulioid, inverted, nonfibrous vascular clusters floating in the stroma present in a range of solid malignant tumors and characterized by frequent vascular/lymphatic vessel invasion and lymph node metastasis. Our results showed that these cell clusters exhibit a stem cell phenotype, supporting the premise that MPC may serve as a promising solid tumor model for studying invasion and metastasis of cancer stem cell clusters. In this review, we discuss the latest advances in MPC research and targeted therapy, focusing on analysis of their stem-like characteristics, mapping their multiomics characteristics, and elucidating the vascular and immune microenvironment of MPC. The existing MPC organoid model was employed to explore potential breakthroughs in targeted therapy and immunotherapy for cancer stem cell clusters.

Submucosal micropapillary adenocarcinoma of the sigmoid colon: A distinct and aggressive subtype of adenocarcinoma

Colorectal invasive micropapillary carcinoma (MPC) is a rare and distinct variant of adenocarcinoma with high incidence of lymph node metastasis. The differential diagnoses of MPC include extensive lymphovascular invasion, metastatic MPC, and retraction artifacts.