Reporting trends, practices, and resource utilization in neuroendocrine tumors of the prostate gland: a survey among thirty-nine genitourinary pathologists

Background: Neuroendocrine differentiation in the prostate gland ranges from clinically insignificant neuroendocrine differentiation detected with markers in an otherwise conventional prostatic adenocarcinoma to a lethal high-grade small/large cell neuroendocrine carcinoma. The concept of neuroendocrine differentiation in prostatic adenocarcinoma has gained considerable importance due to its prognostic and therapeutic ramifications and pathologists play a pivotal role in its recognition. However, its awareness, reporting, and resource utilization practice patterns among pathologists are largely unknown. Methods: Representative examples of different spectrums of neuroendocrine differentiation along with a detailed questionnaire were shared among 39 urologic pathologists using the survey monkey software. Participants were specifically questioned about the use and awareness of the 2016 WHO classification of neuroendocrine tumors of the prostate, understanding of the clinical significance of each entity, and use of different immunohistochemical (IHC) markers. De-identified respondent data were analyzed. Results: A vast majority (90%) of the participants utilize IHC markers to confirm the diagnosis of small cell neuroendocrine carcinoma. A majority (87%) of the respondents were in agreement regarding the utilization of type of IHC markers for small cell neuroendocrine carcinoma for which 85% of the pathologists agreed that determination of the site of origin of a high-grade neuroendocrine carcinoma is not critical, as these are treated similarly. In the setting of mixed carcinomas, 62% of respondents indicated that they provide quantification and grading of the acinar component. There were varied responses regarding the prognostic implication of focal neuroendocrine cells in an otherwise conventional acinar adenocarcinoma and for Paneth cell-like differentiation. The classification of large cell neuroendocrine carcinoma was highly varied, with only 38% agreement in the illustrated case. Finally, despite the recommendation not to perform neuroendocrine markers in the absence of morphologic evidence of neuroendocrine differentiation, 62% would routinely utilize IHC in the work-up of a Gleason score 5 + 5 = 10 acinar adenocarcinoma and its differentiation from high-grade neuroendocrine carcinoma. Conclusion: There is a disparity in the practice utilization patterns among the urologic pathologists with regard to diagnosing high-grade neuroendocrine carcinoma and in understanding the clinical significance of focal neuroendocrine cells in an otherwise conventional acinar adenocarcinoma and Paneth cell-like neuroendocrine differentiation. There seems to have a trend towards overutilization of IHC to determine neuroendocrine differentiation in the absence of neuroendocrine features on morphology. The survey results suggest a need for further refinement and development of standardized guidelines for the classification and reporting of neuroendocrine differentiation in the prostate gland

Reappraisal of Morphological Differences between Renal Medullary Carcinoma, Collecting Duct Carcinoma, and Fumarate Hydratase-Deficient Renal Cell Carcinoma

Renal medullary carcinomas (RMCs) and collecting duct carcinomas (CDCs) are rare subsets of lethal high-stage, high-grade distal nephron-related adenocarcinomas with a predilection for the renal medullary region. Recent findings have established an emerging group of fumarate hydratase (FH)-deficient tumors related to hereditary leiomyomatosis and renal cell carcinoma (HLRCC-RCCs) syndrome within this morphologic spectrum. Recently developed, reliable ancillary testing has enabled consistent separation between these tumor types. Here, we present the clinicopathologic features and differences in the morphologic patterns between RMC, CDC, and FH-deficient RCC in consequence of these recent developments. This study included a total of 100 cases classified using contemporary criteria and ancillary tests. Thirty-three RMCs (SMARCB1/INI1-deficient, hemoglobinopathy), 38 CDCs (SMARCB1/INI1-retained), and 29 RCCs defined by the FH-deficient phenotype (FH/2SC or FH/2SC with FH mutation, regardless of HLRCC syndromic stigmata/history) were selected. The spectrum of morphologic patterns was critically evaluated, and the differences between the morphologic patterns present in the 3 groups were analyzed statistically. Twenty-five percent of cases initially diagnosed as CDC were reclassified as FH-deficient RCC on the basis of our contemporary diagnostic approach. Among the different overlapping morphologic patterns, sieve-like/cribriform and reticular/yolk sac tumor-like patterns favored RMCs, whereas intracystic papillary and tubulocystic patterns favored FH-deficient RCC. The tubulopapillary pattern favored both CDCs and FH-deficient RCCs, and the multinodular infiltrating papillary pattern favored CDCs. Infiltrating glandular and solid sheets/cords/nested patterns were not statistically different among the 3 groups. Viral inclusion-like macronucleoli, considered as a hallmark of HLRCC-RCCs, were observed significantly more frequently in FH-deficient RCCs. Despite the overlapping morphology found among these clinically aggressive infiltrating high-grade adenocarcinomas of the kidney, reproducible differences in morphology emerged between these categories after rigorous characterization. Finally, we recommend that definitive diagnosis of CDC should only be made if RMC and FH-deficient RCC are excluded

Gangliocytic paraganglioma: A rare presentation as intestinal intussusception

Gangliocytic paragangliomas are rare benign neoplastic lesions of neuroendocrine origin occurring primarily in peri-ampullary region. Commonly occurring as small submucosal lesions, presentation as a large polyp with acute ileo-ileal intussusception in a 62-year-old woman is rare and is described in this case report

Hilar/endobronchial NUT midline carcinoma: A case report

Nuclear protein of the testis (NUT) midline carcinoma (NMC) is a rare aggressive tumor described in the midline in the chest and head and neck. Initially reported in younger individuals, it has subsequently been shown to have a wider age distribution. The defining feature of these tumors is its association with BRD-NUT rearrangements. Occasionally NMC has been observed in a non-midline location. This case report describes an unusual rapidly progressing non-midline hilar/endobronchial location of an NMC in a 34-year-old man. The clinical and histologic features were that of an undifferentiated neoplasm concerning for a small cell carcinoma or a lymphoma. A broad panel of immunohistochemical markers for carcinoma, lymphoma and melanoma were negative which led us to suspect a diagnosis of NMC. A positive immunostaining with p63 and NUT protein antigen confirmed the diagnosis. The p63 positivity and cytokeratin negativity suggest a primitive/precursor squamous cell derivation. Keywords: Nuclear protein in testis midline carcinoma, Hilar/endobronchia

Her-2 neu negative lipid rich breast carcinoma in an immunocompromised patient

Lipid-rich breast carcinoma (LRBC) is rare cancer considered to be a variant of invasive ductal breast carcinoma. It is characterized by an aggressive behavior and poor prognosis and requires prompt recognition and close follow-up. The tumor derives its name from the intracytoplasmic neutral lipid that gives it a vacuolated appearance and is included in the current WHO classification. We report here a case of Her-2 neu negative lipid-rich carcinoma of the breast occurring in a HIV positive woman

TP53 structural variants in metastatic prostatic carcinoma.

Sequencing data have been instrumental in identifying oncogenic drivers in prostatic carcinoma and highlighting biomarkers that define aggressive disease. A review of a series of 30 primary and metastatic prostatic carcinomas clinically sequenced at our cancer genomics laboratory utilizing a targeted gene panel identified recurrent structural variants in the TP53 gene. These structural variants were found in 27% of all sequenced cases and represented 36% of the cases with metastatic disease. TP53 structural rearrangements have been previously reported in a significant subset of osteosarcomas, where they result in loss of p53 protein expression by immunohistochemistry. Similarly, in our prostate cases with TP53 structural rearrangements for which tissue was available for testing, we find loss of p53 protein expression by immunohistochemistry. In the eight TP53-rearranged cases, concurrent PTEN loss was identified in 4 cases, TMPRSS2-ERG fusion in 5 cases, and AR and FOXA1 amplification in 1 case each. Our results from this small case series suggest that TP53 rearrangements with loss of expression represent a frequent alternative mechanism of inactivation of this key tumor suppressor gene with potential utility as a marker of aggressive disease. Recognition of this TP53 rearrangement pathway is essential to accurately identify prostatic carcinomas with loss of TP53 function

TP53 structural variants in metastatic prostatic carcinoma.

Sequencing data have been instrumental in identifying oncogenic drivers in prostatic carcinoma and highlighting biomarkers that define aggressive disease. A review of a series of 30 primary and metastatic prostatic carcinomas clinically sequenced at our cancer genomics laboratory utilizing a targeted gene panel identified recurrent structural variants in the TP53 gene. These structural variants were found in 27% of all sequenced cases and represented 36% of the cases with metastatic disease. TP53 structural rearrangements have been previously reported in a significant subset of osteosarcomas, where they result in loss of p53 protein expression by immunohistochemistry. Similarly, in our prostate cases with TP53 structural rearrangements for which tissue was available for testing, we find loss of p53 protein expression by immunohistochemistry. In the eight TP53-rearranged cases, concurrent PTEN loss was identified in 4 cases, TMPRSS2-ERG fusion in 5 cases, and AR and FOXA1 amplification in 1 case each. Our results from this small case series suggest that TP53 rearrangements with loss of expression represent a frequent alternative mechanism of inactivation of this key tumor suppressor gene with potential utility as a marker of aggressive disease. Recognition of this TP53 rearrangement pathway is essential to accurately identify prostatic carcinomas with loss of TP53 function