CDX-2 expression in malignant germ cell tumors of the testes, intratubular germ cell neoplasia, and normal seminiferous tubules

Primary germ cell tumours of the mediastinum: A review with emphasis on diagnostic challenges

This article will review current aspects of the histopathological, immunohistochemical and molecular analysis of primary mediastinal germ cell tumours (PMGCTs) as well as their aetiological, epidemiological, clinical and therapeutic features. PMGCTs represent an important differential diagnosis in the spectrum of mediastinal tumours, and their diagnosis is usually made on small tissue samples from core needle biopsies in combination with diagnostic imaging and serum tumour markers. As in lymphomas, a small biopsy is often the only viable tumour sample available from these patients, as they receive chemotherapy prior to eventual surgical resection. Pathologists therefore need to apply an efficient combination of immunohistochemical markers to confirm the diagnosis of a PMGCT and to exclude morphological mimics.

Complete remission of Cdx-2 positive primary testicular carcinoid tumor: 10-years follow-up and literature review

BACKGROUND

The neuroendocrine cells can cause a variety of malignancies throughout the human body known as the neuroendocrine tumors (NETs) or carcinoid tumors. The primary testicular carcinoid tumor (PTCT) accounts for less than 1% of the testicular neoplasms and for only 0.2% of all carcinoid tumors representing already a very rare neoplastic entity. Here, we present a patient with a history of an exceptionally rare primary testicular carcinoid tumor, staining positive for Cdx-2 along with a literature review.

CASE PRESENTATION

A 44-year old patient without significant past medical history was diagnosed in September 2009 with primary testicular carcinoid tumor, which was surprisingly staining positively for Cdx-2, too. At the time of the initial diagnosis the tumor was already showing histopathological infiltration of veins. DOTA-TATE-PET/CT imaging and endoscopy studies did not show any signs of distant metastases and in particular no gastrointestinal manifestation following no further medical indication for systemic chemotherapy. The continuous and close follow-up of the patient has reached a total of over 10 years at the time of publication remaining in complete remission.

CONCLUSION

The diagnosis of primary testicular carcinoid is based on histopathology. The detailed histopathologic assessment of biomarkers based on immunohistochemistry is very important for the classification and the prognosis of the primary testicular carcinoid tumor. Primary testicular carcinoid tumor with Cdx-2 positive stain outlines an exceptionally rare neoplastic entity without a consensus about general follow-up guidelines, requiring close clinical and imaging aftercare and consideration in Cdx-2 positive metastatic tumor of unknown origin.

Primary Carcinoid Tumor of the Testis: A Case Report and Review of the Literature

Carcinoid tumors usually arise in the gastrointestinal tract. Immunocytohistochemical and radiologic studies are important in detecting the primary tumor site. Primary carcinoid tumors of the testis are particularly rare with a high malignant potential warranting long-term follow-up. We present the case of a primary carcinoid tumor of the testis with long-term surveillance.

Sinonasal SMARCB1 (INI1) Deficient Carcinoma With Yolk Sac Tumor Differentiation: Report of a Case and Comparison With INI1 Expression in Gonadal Germ Cell Tumors

SMARCB1 (INI1) deficient sinonasal carcinoma is a recently recognized entity with wide histomorphologic spectrum. We present a case of this carcinoma that contained, in addition to a "common" morphology, scattered foci of yolk sac tumor differentiation. The tumor occurred in paranasal sinuses in a 44-year-old woman. Immunohistochemically, it was diffusely negative for INI1, whereas an expression of yolk sac tumor markers (α-fetoprotein, glypican-3, CDX2) was limited to the yolk sac tumor component. For comparison with the present case, we performed INI1 immunostaining on a series of 11 gonadal germ cell tumors with yolk sac tumor differentiation. All of these cases showed strong and diffuse expression of INI1, in contrast with the present sinonasal tumor. Our findings expand the morphologic spectrum of SMARCB1 (INI1) deficient sinonasal carcinoma. In addition, we show preliminarily that gonadal germ cell tumors with yolk sac tumor differentiation are not SMARCB1/INI1-deficient.

CDX2 immunostaining in primary and metastatic germ cell tumours of the testis

Objective To evaluate the immunohistochemical staining pattern of caudal type homeobox 2 (CDX2) protein in germ cell tumours (GCTs) of the testis. Methods This study reassessed archival tissue samples collected from patients diagnosed with primary and metastatic testicular GCTs for CDX2 immunoreactivity using standard immunohistochemical techniques. Positive nuclear immunostaining was evaluated with regard to both the staining intensity and the extent of the staining. Results Tissue sections from primary and metastatic testicular GCTs ( n = 104), germ cell neoplasia in situ (GCNis) ( n = 5) and benign testicles ( n = 15) were analysed. The GCNis and benign testicular tissues showed no immunoreactivity for CDX2. Strong and diffuse staining of CDX2 was demonstrated only in the mature colonic epithelium of teratomas in both primary and metastatic GCTs. CDX2 positivity in other tumours (one pure yolk sac tumour, one yolk sac component of a mixed GCT and one pure seminoma) was infrequent, and was only weak and focal. Conclusions CDX2 immunostaining should be interpreted based on both the staining intensity and the extent of staining so as not to cause misdiagnosis. Teratomas with colonic-type epithelium should be considered in the differential diagnosis if a metastatic tumour with an unknown primary shows prominent CDX2 immunostaining.

What Is Trophoblast? A Combination of Criteria Define Human First-Trimester Trophoblast

Controversy surrounds reports describing the derivation of human trophoblast cells from placentas and embryonic stem cells (ESC), partly due to the difficulty in identifying markers that define cells as belonging to the trophoblast lineage. We have selected criteria that are characteristic of primary first-trimester trophoblast: a set of protein markers, HLA class I profile, methylation of ELF5, and expression of microRNAs (miRNAs) from the chromosome 19 miRNA cluster (C19MC). We tested these criteria on cells previously reported to show some phenotypic characteristics of trophoblast: bone morphogenetic protein (BMP)-treated human ESC and 2102Ep, an embryonal carcinoma cell line. Both cell types only show some, but not all, of the four trophoblast criteria. Thus, BMP-treated human ESC have not fully differentiated to trophoblast. Our study identifies a robust panel, including both protein and non-protein-coding markers that, in combination, can be used to reliably define cells as characteristic of early trophoblast.

High-level expression of divergent endodermal lineage markers in gonadal and extra-gonadal yolk sac tumors

Yolk sac tumors occur at both gonadal and extra-gonadal sites. A recent case of ovarian endometrioid-pattern yolk sac tumor with strong diffuse expression of TTF-1 illustrated the potential for misdiagnosis due to divergent expression of endodermal lineage markers. The aim of this study was to investigate the expression of four divergent endodermal lineage markers, TTF-1, CDX2, Hep Par 1, and Napsin A, in gonadal and extra-gonadal yolk sac tumors of differing age, sex, and location (excluding foci of overt hepatoid differentiation). We identified 26 cases (5 ovarian, 15 testicular, and 6 extra-gonadal) containing yolk sac tumor as identified by typical histology and confirmed by positive immunohistochemical staining for alpha-fetoprotein and glypican-3. Mixed or ambiguous foci were confirmed by immunohistochemistry (SALL4 positive and Oct-4 negative). The relative proportion of three histologic patterns: reticular/cystic, solid/myxoid, and glandular was estimated. Percent positivity for the four divergent endodermal lineage markers was compared within yolk sac tumor areas according to site, age group, and histologic pattern. High-level (>25%) staining for one or more divergent endodermal lineage markers was seen in eleven cases: Hep Par 1 in seven cases, all post-pubertal, TTF-1 in four cases, two ovarian and two extra-gonadal, and CDX2 in three cases, with no age or site predilection. No case highly expressed all three divergent endodermal lineage markers, but four co-expressed high levels of two markers: two ovarian yolk sac tumors with TTF-1 and Hep Par 1, one testicular yolk sac tumor with CDX2 and Hep Par 1, and one extra-gonadal yolk sac tumors with TTF-1 and CDX2. While no absolute correlation of high-level divergent endodermal lineage marker expression with histologic subtype was observed, TTF-1 and CDX2 expression was predominantly seen in reticular/cystic and glandular areas while Hep Par 1 was most frequent in myxoid/solid and glandular areas.

Atypical teratoid/ rhabdoid tumor, an immunohistochemical study of potential diagnostic and prognostic markers

Atypical teratoid/rhabdoid tumor (AT/RT) is a rare tumor of the CNS mostly seen in infants and is often associated with a dismal outcome. Despite the heterogeneous morphology and/or immunoprofile, its diagnosis nowadays relies on the negative INI-1/BAF47 nuclear immunostain in tumor cells. We aim to investigate a number of immunohistochemical antibodies as potential diagnostic and prognostic markers. All AT/RT cases in patients younger than 18 years of age were included. Demographics, clinical features and outcome were collected. Immunostains tested included SALL-4, OCT3/4, CD99, FLI-1, cyclin-D1, β-catenin, P53, P16, CDX2 and WT-1. Nineteen cases (10 males) were identified at our center between 2004-2013 with a median age of 24 months. Ten (52.6%) cases were supratentorial. Six (42.9%) cases showed metastasis at time of presentation. Chemotherapy was administered to 10 (62.5%) and radiotherapy to seven (43.8%). The median overall survival was 11 months. A single long-term survival of 104 months was identified. Pathologically, most cases showed an admixture of rhabdoid cells and/or small cells and/or pale cells in variable proportions. Of all tested antibodies, only positivity for FLI-1 was associated with improved survival (P = 0.0012), while positivity for cyclin-D1 showed a trend toward improved survival (P = 0.0547). CDX2 was positive only in the single long-term survival. Interestingly, two cases showed co-expression of CD99 and FLI-1, and some were positive for SALL-4. In conclusion, FLI-1 and cyclin-D1 are potential prognostic markers associated with better outcome. Occasional AT/RT cases might co-express CD99 and FLI-1 as well as SALL-4, a potential diagnostic pitfall with Ewing sarcoma/ primitive neuroectodermal tumors and germ cell tumors, respectively.

Spermatogonial stem cell functions in physiological and pathological conditions

Sperm have a vital role in the continuity of a species by contributing genetic information to the next generation. Production of these specialized gametes in numbers sufficient to confer normal fertility occurs via cycling of the spermatogenic lineage, a process referred to as spermatogenesis. Continuity relies on the activities of a self-renewing reservoir of spermatogonial stem cells (SSCs) from which progenitors will arise that transiently amplify in number before committing to a pathway of terminal differentiation. A primary population of SSCs is established during neonatal development from a pool of quiescent gonocyte precursors that forms in embryogenesis. Disruption of this process has dire consequences on maintenance of a cycling spermatogenic lineage in adulthood. At present, the molecular mechanisms underlying initial formation of the SSC pool are largely undefined. However, several transcription factors and posttranscriptional regulators have been identified as important regulators of SSC self-renewal from studies with mutant mouse models and experimental manipulation within primary cultures of mouse SSCs. Importantly, loss of function of these self-renewal factors may be underlying causes of infertility. Furthermore, disruption in the establishment of the SSC state within gonocytes or misregulation of self-renewal may manifest as testicular germ cell tumors in postnatal life.

Columnar cell variant of papillary thyroid carcinoma: a study of 10 cases with emphasis on CDX2 expression

BACKGROUND

Columnar cell variant is a recognized rare variant of papillary thyroid carcinoma (PTC) that has an uncertain clinical course. This variant has two subvariants, and one is regarded as a more aggressive form in comparison to the more common classical and follicular variants. These tumors have morphological resemblance with endometrial or colonic adenocarcinoma. CDX2, a transcription factor of the caudal homeobox family, plays a key role in intestinal development and differentiation, and it is widely used as a marker to detect adenocarcinomas of intestinal and colonic origin. CDX2 has been rarely reported in PTC.

METHODS

We studied 10 cases of columnar cell variant of PTC (CCV-PTC). The histological, architectural, and cytological features fulfilled the diagnostic criteria of the CCV-PTC, as defined by the current World Health Organization classification. Ten patients (six men and four women) ranging in age from 32 to 90 years (mean, 58.3 years) presented with tumors classified as indolent (four cases) or aggressive (six cases); three harbored a BRAF(V600E) mutation. All cases were β-catenin negative. The Ki-67 proliferative index was up to 50%. All cases were thyroid transcription factor-1-positive. Using paraffin-embedded blocks, immunohistochemistry for CDX2 was performed to evaluate the reactivity of this antibody to this variant of PTC.

RESULTS

Nuclear positivity for CDX2 was detected in one out of the 10 cases studied (10%); the other nine cases did not express CDX2.

CONCLUSION

Only one of our cases showed nuclear positivity for CDX2. Therefore, our study failed to confirm it as a marker for CCV-PTC. The absence of CDX2 in the majority of the cases does not support the theory of CDX2 playing a role in the intestinal phenotype of these tumors.