Expression of the intestinal marker Cdx2 in secondary adenocarcinomas of the colorectum

Immunocytochemistry of effusions: Processing and commonly used immunomarkers

Definitive cytopathological interpretation of some of the effusion fluids may not be possible based on cytomorphological evaluation alone. As discussed in other reviews, this is due to various reasons specifically applicable to effusion fluids including remarkably wide morphologic spectrum of reactive mesothelial cells overlapping with some well to moderately differentiated metastatic carcinoma. The challenge is subject to various factors including level of interpreter training or experience, institutional demographics (such as type of prevalent diseases, predominant sex and age group), technical advances in ancillary support, and expertise in cytopreparatory processing. In such cases immunohistochemistry performed on cell-block sections is simple objective adjunct with or without other ancillary techniques. Ongoing increase in number of immunomarkers along with rabbit monoclonal antibodies with relatively higher affinity is further refining this field. SCIP (subtractive coordinate immunoreactivity pattern) approach, discussed as separate dedicated review article, facilitates refined interpretation of immunoreactivity pattern in coordinate manner on various serial sections of cell-blocks. However, many variables such as delay after specimen collection, specimen processing related factors including fixation and storage; ambient conditions under which paraffin blocks are archived (for retrospective testing); antigen retrieval method; duration of antigen retrieval step; antibody clone and dilution; and antibody application time are common with application of immunohistochemistry in other areas. This review is dedicated to highlight technical aspects including processing of effusion specimens for optimum immunocytochemical evaluation along with commonly used immunomarkers in effusion cytopathology. This review focuses on the technical and general information about various immunomarkers.

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.

SATB2 Versus CDX2: A Battle Royale for Diagnostic Supremacy in Mucinous Tumors

CONTEXT.—

Metastatic mucinous tumors present a diagnostic challenge for pathologists as tumor histomorphology is often nonspecific and optimal immunoprofiles are still under investigation.

OBJECTIVE.—

To present a head-to-head comparison of special AT-rich sequence-binding protein 2 (SATB2) and caudal type homeobox 2 (CDX2) expression in a diverse array of primary mucinous tumors.

DESIGN.—

SATB2 and CDX2 immunohistochemical stains were performed on whole sections from 44 mucinous colorectal carcinomas and 175 noncolorectal mucinous tumors. A nuclear scoring system measuring intensity (0-3+) and percentage staining (0 = <5%, 1 = 5%-49%, 2 = ≥50%) was implemented, producing an additive histologic score (H-score).

RESULTS.—

SATB2 demonstrated acceptable accuracy at low to moderate expression levels (H-scores of 1-4). With these H-score cutoffs, overall accuracy was greater than 90%. In contrast, CDX2's accuracy rivaled that of SATB2 only at an H-score of 5 (89.0%), as its specificity suffered at lower expression levels (<70.0% at H-scores of 1-4). Using a moderate H-score cutoff of 3 or higher, significant differences for both sensitivity and specificity were identified between SATB2 and CDX2 (P = .01 for sensitivity and P < .001 for specificity), though these stains were near equivalent when each was interpreted as positive at its respective optimal H-score (SATB2 ≥ 3 and CDX2 = 5).

CONCLUSIONS.—

SATB2 is a more accurate marker of colorectal origin across a variety of expression levels compared with CDX2 when applied to mucinous tumors from a host of primary sites. However, these stains are near equivalent when each is interpreted at its optimal expression level.

A Rare Case of Endometrial Cancer Metastatic to the Sigmoid Colon and Small Bowel

Metastatic endometrial cancer to the small bowel or colon has been described but is quite rare. We present a case of metastatic endometrial cancer with synchronous metastases to the colon and jejunum identified three years after surgical treatment of early stage endometrial cancer.

Efficacy of Immunohistochemical Staining in Differentiating a Squamous Cell Carcinoma in Poorly Differentiated Rectal Cancer: Two Case Reports

A rectal carcinoma, including primary an adenosquamous and a squamous cell carcinoma (SCC), is a very rare disease, accounting for 0.025% to 0.20% of all large-bowel malignant tumors. Because SCCs have a higher mortality than adenosquamous carcinomas, determining whether the primary rectal cancer exhibits an adenomatous component or a squamous component is important. While differentiating between these 2 components, especially in poorly differentiated rectal cancer, is difficult, specific immunohistochemical stains enable accurate diagnoses. Here, we report the use of immunohistochemical stains to distinguish between the adenomatous and the squamous components in 2 patients with low rectal cancer, a 58-year-old man and a 73-year-old woman, who were initially diagnosed using the histopathologic results for a poorly differentiated carcinoma. These data suggest that using these immunohistochemical stains will help to accurately diagnose the type of rectal cancer, especially for poorly differentiated carcinomas, and will provide important information to determine the proper treatment for the patient.

Utilization of Wilms' tumor 1 antigen in a panel for differential diagnosis of ovarian carcinomas

Objective:

Ovarian metasteses are often mistaken for primary adenocarcinoma. Studies conducted in recent years have focused on a search for an immunohistochemical marker to aid the differential diagnosis primary and metastatic ovarian carcinoma. Our study objective was to study the usefulness of Wilms tumor 1 (WT 1) antigen in this context.

Materials and Methods:

The study was conducted at the pathology clinic of Lütfi Kırdar Training and Research Hospital. Deparaffinated blocks of 40 epithelial ovarian tumors, 40 colon adenocarcinomas, and 35 cases of omentum metastases were studied. Cytokeratin 7 (CK 7), cytokeratin 20 (CK 20), and WT 1 were applied to all specimens.

Results:

All ovarian adenocarcinomas were stained with CK 7 (100%). Colorectal adenocarcinomas were stained positive with CK 20 in 87.5% of cases. Primary ovarian adenocarcinomas stained positive with WT 1 in 82.5% of the cases and none of the colorectal adenocarcinomas showed staining with WT 1 (0%).

Conclusion:

WT 1 can be used in conjuction with CK 7 in the differential diagnosis of ovarian carcinomas.

Practical Applications in Immunohistochemistry: Carcinomas of Unknown Primary Site

CONTEXT

-Identification of the site of origin of carcinoma of unknown primary using immunohistochemistry is a frequent requirement of anatomic pathologists. Diagnostic accuracy is crucial, particularly in the current era of targeted therapies and smaller sample sizes.

OBJECTIVES

-To provide practical guidance and suggestions for classifying carcinoma of unknown primary using both proven and new antibodies, as well as targeting panels based on integration of morphologic and clinical features.

DATA SOURCES

-Literature review, the authors' practice experience, and authors' research.

CONCLUSIONS

-With well-performed and interpreted immunohistochemistry panels, anatomic pathologists can successfully identify the site of origin of carcinoma of unknown primary. It is crucial to understand not only the diagnostic uses of the many available antibodies but also the potential limits and pitfalls.

Metastatic pancreatic carcinoma presenting as colon carcinoma

Determining the origin of poorly differentiated adenocarcinomas remains a challenge for the pathologist. This manuscript reports the use of a panel of specific immunohistochemical stains to determine the primary site of a tumor in the colon. A 45-year-old man had a right hemicolectomy for adenocarcinoma. Immunohistochemical staining documented that the lesion was a metastasis from a primary pancreatic adenocarcinoma--an unusual pattern of spread. The case emphasizes the important use of immunohistochemistry in identifying the primary source of lesions, allowing for appropriate treatment and staging.

Colonic carcinoma metastatic to the endometrium: the importance of clinical history in averting misdiagnosis as a primary endometrial carcinoma

Metastases to endometrium are a rare event. A case of a 53-year-old woman with a previous colon cancer presenting with a dysfunctional uterine bleeding is reported. The curettage specimens consisted of multiple fragments of proliferative endometrial tissue mixed with irregular glands, focally amputated, lined by very cells with elongated, hyperchromatic nuclei and solid sheets of neoplastic cells often filled with necrotic debris and inflammatory cells, resembling endometrioid adenocarcinoma. Neoplastic cells resulted positive at immunohistochemical reaction for CK20, CDX2, p53 and negative for CK7, vimentin, ER, and PR suggesting a metastatic colon adenocarcinoma. Absence of premalignant changes, such as hyperplasia, besides frankly malignant glands in an endometrial curette should be regarded as an alarming feature for a secondary nature mostly from large bowel. In these cases clinical history is crucial and an immunohistochemical panel made up of CK7, CK20, CDX2, p53, vimentin, ER, and PR is useful for the correct diagnosis.

Cdx2, cytokeratin 20, thyroid transcription factor 1, and prostate-specific antigen expression in unusual subtypes of prostate cancer

There are some unusual histologic variants of prostate carcinoma, including mucinous, signet-ring cells, and ductal carcinomas that can metastasize in a problematic way and simulate lung, colorectal, or bladder primaries. Currently, antibodies that are organ-specific have been used in the routine surgical pathology practice. Our aim is to study the profile of expression of Cdx2, thyroid transcription factor 1 (TTF1), and cytokeratin 20 (CK20) in prostate cancer with unusual histologic finding. Twenty-nine prostate adenocarcinomas with unusual histologic findings were submitted to immunohistochemistry with prostate-specific antigen (PSA), CK20, Cdx2, and TTF1 antibodies. There were 7 mucinous, 5 ductal, 2 signet-ring cells, and 15 usual acinar adenocarcinomas with focal mucinous differentiation. To compare the results with usual acinar adenocarcinomas, we studied 10 primary and their respective lymph node metastases in a tissue microarray, 2 unusual metastatic adenocarcinomas, and 6 usual acinar high-grade carcinomas. For tumors with special histologic finding, Cdx2 was expressed by 9 (31.0%) mucinous, signet-cell, or with focal mucinous differentiation. Thyroid transcription factor 1 was moderately positive in mucinous differentiation areas of 2 (6.9%) adenocarcinomas. Cytokeratin 20 was expressed by 9 (31.0%) tumors, among them, 3 ductal adenocarcinomas. Prostate-specific antigen was positive in 28 (96.6%) cases and negative in 1 ductal adenocarcinoma. There was only 1 worrisome ductal adenocarcinoma that was strongly CK20 positive and PSA negative. Almost one third of mucinous prostate carcinomas express Cdx2. Cytokeratin 20 can be positive also in one third of prostate carcinomas, especially the ductal type. Pathologist should be alert when evaluating immunohistochemical profiles of unusual histologic findings of prostate cancer, mostly in distant sites.