Clinical implications of lung neuroendocrine neoplasm classification.

INTRODUCTION: Neuroendocrine neoplasms of the lung (Lung NENs) encompass NE tumors (NETs), which are in turn split into typical and atypical carcinoids, and NE carcinomas (NECs), which group together small-cell carcinoma and large-cell NE carcinoma. This classification is the current basis for orienting the daily practice of these patients, with diagnostic, prognostic, and predictive inferences. AREAS COVERED: The clinical implications of lung NEN classification are addressed according to three converging perspectives, which were dissected through an extensive literature overview: (1) how to put intratumor heterogeneity into the context of the current classification; (2) how to contextualize immunohistochemistry markers to improve diagnosis, prognosis, and therapy prediction; and (3) how to use immuno-oncology strategies for life-threatening NECs, which still account for 90% or more of lung NENs. EXPERT OPINION: We provide practical insights to account for intratumor heterogeneity, practice the choice of immunohistochemistry markers, and emphasize once again the added value of immuno-oncology in the setting of personalized medicine of lung NENs.

Identification of potential serum biomarkers for simultaneously classifying lung adenocarcinoma, squamous cell carcinoma and small cell carcinoma.

BACKGROUND: Histological subtypes of lung cancer are crucial for making treatment decisions. However, multi-subtype classifications including adenocarcinoma (AC), squamous cell carcinoma (SqCC) and small cell carcinoma (SCLC) were rare in the previous studies. This study aimed at identifying and screening potential serum biomarkers for the simultaneous classification of AC, SqCC and SCLC. PATIENTS AND METHODS: A total of 143 serum samples of AC, SqCC and SCLC were analyzed by 1HNMR and UPLC-MS/MS. The stepwise discriminant analysis (DA) and multilayer perceptron (MLP) were employed to screen the most efficient combinations of markers for classification. RESULTS: The results of non-targeted metabolomics analysis showed that the changes of metabolites of choline, lipid or amino acid might contribute to the classification of lung cancer subtypes. 17 metabolites in those pathways were further quantified by UPLC-MS/MS. DA screened out that serum xanthine, S-adenosyl methionine (SAM), carcinoembryonic antigen (CEA), neuron-specific enolase (NSE) and squamous cell carcinoma antigen (SCC) contributed significantly to the classification of AC, SqCC and SCLC. The average accuracy of 92.3% and the area under the receiver operating characteristic curve of 0.97 would be achieved by MLP model when a combination of those five variables as input parameters. CONCLUSION: Our findings suggested that metabolomics was helpful in screening potential serum markers for lung cancer classification. The MLP model established can be used for the simultaneous diagnosis of AC, SqCC and SCLC with high accuracy, which is worthy of further study.

[Diagnosis of lung biopsy employing the 2015 WHO criteria and detection of related oncogenic driver mutations].

Objective: The diagnostic criteria of lung biopsy specimens by 2015 WHO lung tumor classification were used to evaluate lung biopsy specimens along with detection of genetic alterations of major tumor driving genes including epidermal growth factor receptor (EGFR). Methods: The clinical data, histological slides, immunohistochemical stains and special stains of 806 lung biopsy specimens at Beijing Hospital from July 2015 to July 2018 were retrospectively analyzed. Diagnosis of lung cancer was reclassified according to the 2015 WHO lung tumor classification and related gene mutation data were analyzed. Results: During a three-year period, the total number of lung cancer diagnosis was 483 cases, including 221 female and 262 male patients with age ranging from 37 to 85 years (median age of 65 years). There were 40 cases(8.28%) of small cell carcinoma,11 cases (2.28%) of large cell neuroendocrine carcinoma, 3 cases (0.62%) of combined neuroendocrine carcinoma, 2 cases(0.41%) of atypical carcinoid, 208 cases (43.06%) of adenocarcinoma, 92 cases(19.05%) of non-small cell carcinoma, favor adenocarcinoma, 66 cases (13.66%) of squamous cell carcinoma, 42 cases(8.70%) of non-small cell carcinoma, favor squamous cell carcinoma, 16 cases(3.31%) of non-small cell carcinoma, not otherwise specified, and 3 cases (0.62%) of non-small cell carcinoma, possible adenosquamous carcinoma. Among 202 cases tested, 107 cases (52.97%) showed EGFR mutations, including 86 of 133 cases (64.66%) of adenocarcinoma and 18 of 52 cases (34.62%) of non-small cell carcinoma, favor adenocarcinoma. Twenty two cases were found to have T790M mutation among 27 patients after EGFR TKI targeted drug therapy. Immunohistochemical staining of ALK (D5F3) was positive in 3 of 354 cases of non-small cell lung cancer, confirmed by EML4-ALK fusion gene fluorescence PCR. ROS1 gene fusion was found in 1 of 38 cases. Splicing mutations in exon 14 of MET gene were seen in one case of non-small cell carcinoma with spindle cell differentiation. Conclusion: The new diagnostic criteria by the 2015 WHO lung tumor classification is better suited for diagnosing lung biopsy specimens and providing accurate treatment guidance and improving the patient outcome.

Multimodal molecular analysis of an atypical small cell carcinoma of the ovary, hypercalcemic type.

A 12-yr-old normocalcemic female treated for a ruptured ovarian juvenile granulosa cell tumor at an outside hospital presented for exploratory laparotomy and gross surgical debulking of pelvic recurrence. Morphologically, the tumor was composed of sheets and nests of small blue cells forming cysts of various sizes and focal mucinous differentiation. Epithelial membrane antigen (EMA), patchy inhibin, and strong and diffuse p53 immunoreactivity were also observed. A revised diagnosis of mixed sex cord stromal tumor with heterologous elements was favored because of the inhibin immunoreactivity. Targeted next-generation sequencing of the tumor revealed a SMARCA4 c.1141C>T, p.Arg381Ter (NM_001128849.1) nonsense mutation and an in-frame 18-bp TP53 deletion (c.594_611del18, p.Gly199_Glu204del, NM_001126112.2). Cytogenetic analysis revealed a normal 46,XX karyotype, and OncoScan single-nucleotide polymorphism array analysis demonstrated copy-neutral loss of heterozygosity (CN-LOH) of 19p13.3-19p13.2 and mosaic CN-LOH of 17p13.3-p11.2 encompassing the SMARCA4 and TP53 loci, respectively. Subsequent germline SMARCA4 sequencing confirmed a heterozygous SMARCA4 p.Arg381Ter mutation. In lieu of the molecular findings, the diagnosis was amended to small cell carcinoma of the ovary, hypercalcemic type (SCCOHT). The patient was treated aggressively with paclitaxel, carboplatin, and bevacizumab. She received an autologous stem cell transplant but died 5 mo after SCCOHT diagnosis secondary to complications of the transplant. This case expands the morphologic, immunophenotypic, and genomic spectrum of SCCOHT and highlights how multimodal molecular analysis can assist with the diagnosis and clinical management of SCCOHT patients.

Validation of the AJCC 8th lung cancer staging system among patients with small cell lung cancer

Background. The current study tried to validate the prognostic significance of the 8th American Joint Committee on Cancer (AJCC) staging system among small cell lung cancer (SCLC) patients recorded within the surveillance, epidemiology, and end results (SEER) database. Patients and methods. SEER database (2004-2014) has been queried through SEER*Stat program, and both AJCC 7th and 8th edition stages were constructed. Cancer-specific and overall survival analyses according to both editions were performed through Kaplan-Meier analysis. The cause-specific Cox regression hazard for both AJCC editions (adjusted for age, gender, race, and surgery) was calculated and pair-wise comparisons of hazard ratios were conducted. Results. A total of 39,286 patients with SCLC were recruited in the period from 2004 to 2014. For overall and cancer-specific survival assessment, according to the AJCC 7th edition, P values for all pair-wise comparisons among different stages were significant (<0.0001) except for the comparisons between stage IB vs. stage IIA, and stage IIB vs. stage IIIA. For overall survival assessment, according to AJCC 8th, P values for all pair-wise comparisons were significant (<0.05) except for IA2 vs. IA3, IA3 vs. IB, IB vs. IIA, IIA vs. IIB, and IIIB vs. IIIC. For cancer-specific survival, according to AJCC 8th, P values for all pair-wise comparisons among different stages were significant (<0.05) except IA1 vs. IA2, IA2 vs. IA3, and IIA vs. IIB. When conducting pair-wise hazard ratio comparisons among different AJCC stages (for both editions), similar findings to the Kaplan-Meier analyses were reported. Conclusion. While there is a clear improvement for both the AJCC 7th and 8th systems compared to the old veterans’ administration system, there is a modest improvement for the 8th compared to the 7th system among patients with SCLC (AU)

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8ª Edición de la clasificación TNM del cáncer de pulmón / No disponible

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[Grading of lung cancer]. / Grading von Lungenkarzinomen.

In comparison with other tumor entities there is no common generally accepted grading system for lung cancer with clearly defined criteria and clinical relevance. In the recent fourth edition of the World Health Organization (WHO) classification from 2015 of tumors of the lungs, pleura, thymus and heart, there is no generally applicable grading for pulmonary adenocarcinomas, squamous cell carcinomas or rarer forms of carcinoma. Since the new IASLC/ATS/ERS classification of adenocarcinomas published in 2011, 5 different subtypes with significantly different prognosis are proposed. This results in an architectural (histologic) grading, which is usually applied to resection specimens. For squamous cell carcinoma the number of different histological subtypes in the new WHO classification was reduced compared to earlier versions but without a common grading system. In recent publications nesting and budding were proposed as the main (histologic) criteria for a grading of squamous cell carcinomas. The grading of neuroendocrine tumors (NET) of the lungs in comparison with NET in other organs is presented in a separate article in this issue. Certain rare tumor types are high grade per definition: small cell, large cell and pleomorphic carcinomas, carcinosarcomas and pulmonary blastomas. In the future it is to be expected that these developments will be further refined, e. g. by adding further subtypes for adenocarcinomas and cytologic and/or nuclear criteria for adenocarcinoma and/or squamous cell carcinomas.

[Specific types of bladder cancer]. / Spezifische Typen des Harnblasenkarzinoms.

Bladder cancer shows rare variants and special subtypes with diverse prognostic importance and therefore may necessitate different therapeutic approaches. For pathologists it is important to histologically diagnose and specify such variants. Nested variants of urothelial carcinoma with inconspicuous, well-formed tumor cell nests present with an aggressive course. The plasmacytoid variant, which morphologically resembles plasma cells is associated with a shorter survival time and a high frequency of peritoneal metastasis. Micropapillary urothelial carcinoma with small papillary tumor cell islands within artificial tissue retraction spaces and frequent lymphovascular invasion also has a poor prognosis. Other important rare differential variants listed in the World Health Organization (WHO) classification are microcystic, lymphoepithelioma-like, sarcomatoid, giant cell and undifferentiated urothelial carcinomas. Additionally, there are three special types of bladder cancer: squamous cell carcinoma, adenocarcinoma and small cell neuroendocrine carcinoma of the bladder. These tumors are characterized by pure squamous cell or glandular differentiation and are sometimes less responsive to adjuvant (chemo)therapy. Small cell carcinoma of the bladder mimics the neuroendocrine features of its pulmonary counterpart, shows an aggressive course but is sensitive to (neo-)adjuvant chemotherapy. The morphology and histology of the most important variants and special types are discussed in this review.

[Pulmonary neuroendocrine tumors in the new WHO 2015 classification: Start of breaking new grounds?]. / Pulmonale neuroendokrine Tumoren in der neuen WHO-Klassifikation 2015 : Beginn eines Aufbruchs zu "neuen Ufern"?

CLASSIFICATION: In the recently published 4th edition of the World Health Organization (WHO) classification of tumors of the lungs, pleura, thymus and heart, all neuroendocrine tumors of the lungs (pNET) are presented for the first time in one single chapter following adenocarcinoma and squamous cell carcinoma and before large cell carcinoma. In this classification, high grade small cell lung cancer (SCLC) and large cell neuroendocrine carcinoma (LCNEC) are differentiated from intermediate grade atypical carcinoids (AC) and low grade typical carcinoids as well as from preinvasive lesions (DIPNECH). In the 3rd WHO classification from 2004, which dealt with resection specimens, SCLC and carcinoids each had a separate chapter and LCNEC was previously listed in the chapter on large cell carcinoma of the lungs. The new WHO classification is for the first time also applicable to lung biopsies. DIAGNOSTICS: Normally, common features of all pNET are a neuroendocrine morphology (as far as detectable in small biopsies) and expression of the neuroendocrine (NE) markers (chromogranin A, synaptophysin and CD56/NCAM). An immunohistochemical positive staining of at least one NE marker was already recommended in the 3rd edition of the WHO classification (2004) only for LCNEC. Differentiating features are a small or large cell cytomorphology/histomorphology, nuclear criteria and the mitotic rate (for SCLC >10 with a median of 80, for LCNEC >10 median 70, for AC 2 - 10, for TC < 2 each per 2 mm(2)). Tumor cell necrosis usually occurs in SCLC and LCNEC, partially in AC and not in TC. The guideline Ki67 proliferation rates are given for the first time in the new WHO classification for SCLC as 50-100 %, for LCNEC 40-80 %, for AC up to 20 % and for TC up to 5 %. MOLECULAR PATHOLOGY: Molecular alterations occur in SCLC and LCNEC in large numbers and are very variable in quality. In AC and TC they occur much less frequently and are relatively similar. CONCLUSION: The direct comparison of all pNET in one chapter facilitates the differential diagnostics of these tumors, provides a better transparency especially of LCNEC and allows a further comprehensive development of the clinical practical and scientific evaluation of pNET. Although a separate terminology of pNET is maintained for the lungs, a careful approach towards the gastroentero-pancreatic NET (gepNET) can be observed.

Germline SMARCA4 mutations in patients with ovarian small cell carcinoma of hypercalcemic type.

BACKGROUND: SMARCA4 mutations have recently been identified as driving lesions of the ovarian small cell carcinoma of hypercalcemic type (SCCHT). Familial occurrence of this neoplasm was described previously. METHODS: We looked for germline SMARCA4 alterations in eight patients with the SCCHT. DNA was extracted from probands' and their relatives' blood. The SMARCA4 coding sequence, previously found altered in all the tumors, was PCR amplified and sequenced in the germline DNA. RESULTS: Two patients carried a heterozygous germline SMARCA4 alteration: c.3760G > T and c.2352insG, respectively. The analysis of the probands' next of kins revealed that the c.3760G > T mutation was inherited by the proband and her sister from their father, and the sisters' four children also carried the mutation. The proband's sister was diagnosed with a carcinoma of the parotid gland at age 2. A brother of the other proband was tested negative. CONCLUSIONS: Our study suggests that some women develop the ovarian SCCHT due to the inherited or possibly de novo-occurring germline alterations in the SMARCA4 gene, however, its penetrance appears limited. Nevertheless, because of high aggressiveness of the SCCHT, a molecular diagnostics of the SMARCA4 gene and careful follow-up should be offered to patients with this cancer and their families.

The hypoxic tumor microenvironment: driving the tumorigenesis of non-small-cell lung cancer.

Since the application of molecular biology in cancer biology, lung cancer research has classically focused on molecular drivers of disease. One such pathway, the hypoxic response pathway, is activated by reduced local oxygen concentrations at the tumor site. Hypoxia-driven gene and protein changes enhance epithelial-to-mesenchymal transition, remodel the extracellular matrix, drive drug resistance, support cancer stem cells and aid evasion from immune cells. However, it is not the tumor cells alone which drive this response to hypoxia, but rather their interaction with a complex milieu of supporting cells. This review will focus on recent advances in our understanding of how these cells contribute to the tumor response to hypoxia in non-small-cell lung cancer.

[Neuroendocrine tumors of the lungs. From small cell lung carcinoma to diffuse idiopathic pulmonary neuroendocrine cell hyperplasia]. / Neuroendokrine Tumoren der Lunge. Vom kleinzelligen Lungenkarzinom bis zur diffusen idiopathischen pulmonalen neuroendokrinen Zellhyperplasie.

The new World Health Organization (WHO) classification announced for 2015 will for the first time present all neuroendocrine tumors (NET) of the lungs in one single section. In this classification high grade small cell lung carcinoma (SCLC) and large cell neuroendocrine carcinoma (LCNEC) will be discriminated from intermediate grade atypical carcinoid (AC) and low grade typical carcinoid as well as from the preinvasive lesion diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH). The LCNEC was previously listed under the section of large cell carcinomas. The LCNEC could previously be diagnosed according to the current WHO classification from 2004 which is designed for resection specimens. According to this the main diagnostic criteria are a neuroendocrine growth pattern which can be difficult or impossible to detect in biopsy material, non-small cell cytological features, more than 10 mitoses per 2 mm(2) (mean 70-80 per 2 mm(2)), tumor cell necrosis, and an immunohistochemical positivity for at least one neuroendocrine marker other than neuron-specific enolase (NSE). The presentation of all neuroendocrine tumors of the lungs in one section allows a more direct comparison and a better differential diagnostic discrimination of the different entities.

[Molecular pathology of lung cancer. State of the art 2014]. / Molekularpathologie des Lungenkarzinoms. "State of the art" 2014.

Lung cancer is the most frequent cause of cancer-related death in Germany in men and women alike. While in the last decades a classification of epithelial lung tumors into non-small cell and small cell lung cancer was clearly sufficient from the therapeutic viewpoint, the dawn of the era of personalized medicine together with tremendous developments in the field of high throughput technologies have led to a molecular individualization of these tumors and, even more important, to a molecularly defined individualization of tumor therapy. This development resulted in the definition of a wide array of molecularly divergent tumor families. In this article we will give an overview on relevant molecular alterations in non-small cell lung cancers, comprising adenocarcinomas, squamous cell carcinomas and large cell carcinomas and also small cell carcinomas and carcinoids. Besides some similarities data gathered in the last few years specifically highlighted the immense diversity of molecular alterations that might underlie tumorigenesis of lung neoplasms. The knowledge on how to detect these alterations is of utmost importance in pathology, as treatment decisions are increasingly based on their presence or absence, putting molecular pathology in the central focus of the novel era of personalized medicine in oncology.

Proposed morphologic classification of prostate cancer with neuroendocrine differentiation.

On July 31, 2013, the Prostate Cancer Foundation assembled a working committee on the molecular biology and pathologic classification of neuroendocrine (NE) differentiation in prostate cancer. New clinical and molecular data emerging from prostate cancers treated by contemporary androgen deprivation therapies, as well as primary lesions, have highlighted the need for refinement of diagnostic terminology to encompass the full spectrum of NE differentiation. The classification system consists of: Usual prostate adenocarcinoma with NE differentiation; 2) Adenocarcinoma with Paneth cell NE differentiation; 3) Carcinoid tumor; 4) Small cell carcinoma; 5) Large cell NE carcinoma; and 5) Mixed NE carcinoma - acinar adenocarcinoma. The article also highlights "prostate carcinoma with overlapping features of small cell carcinoma and acinar adenocarcinoma" and "castrate-resistant prostate cancer with small cell cancer-like clinical presentation". It is envisioned that specific criteria associated with the refined diagnostic terminology will lead to clinically relevant pathologic diagnoses that will stimulate further clinical and molecular investigation and identification of appropriate targeted therapies.

A retrospective study of the prevalence and classification of intestinal neoplasia in zebrafish (Danio rerio).

For over a decade, spontaneous intestinal neoplasia has been observed in zebrafish (Danio rerio) submitted to the ZIRC (Zebrafish International Resource Center) diagnostic service. In addition, zebrafish displayed preneoplastic intestinal changes including hyperplasia, dysplasia, and enteritis. A total of 195 zebrafish, representing 2% of the total fish submitted to the service, were diagnosed with these lesions. Neoplastic changes were classified either as adenocarcinoma or small cell carcinoma, with a few exceptions (carcinoma not otherwise specified, tubular adenoma, and tubulovillous adenoma). Tumor prevalence appeared similarly distributed between sexes and generally occurred in zebrafish greater than 1 year of age, although neoplastic changes were observed in fish 6 months of age. Eleven lines displayed these preneoplastic and neoplastic changes, including wild-types and mutants. Affected zebrafish originated from 18 facilities, but the majority of fish were from a single zebrafish research facility (hereafter referred to as the primary facility) that has submitted numerous samples to the ZIRC diagnostic service. Zebrafish from the primary facility submitted as normal sentinel fish demonstrate that these lesions are most often subclinical. Fish fed the diet from the primary facility and held at another location did not develop intestinal lesions, indicating that diet is not the etiologic agent.

The 2002 AJCC TNM classification is a better predictor of primary small cell esophageal carcinoma outcome than the VALSG staging system.

Small cell carcinoma of the esophagus (SCCE) is a rare and aggressive malignant tumor with a poor prognosis. The optimal disease staging system and treatment approaches have not yet been defined. This study aimed to evaluate the prediction of different staging systems for prognosis and treatment options of SCCE. We retrospectively accessed the clinicopathologic characteristics, treatment strategy, and prognosis of 76 patients diagnosed with primary SCCE between 2001 and 2011. The 1-, 2-, 3-, and 5-year overall survival rates were 58%, 31%, 19%, and 13%, respectively. Univariate analysis showed that the 2002 American Joint Committee on Cancer (AJCC) tumor-node-metastasis (TNM) classification (P = 0.002), Veterans Administration Lung Study Group (VALSG) stage (P = 0.001), predisposing factors (P < 0.001), T category (P = 0.023), and M category (P < 0.001) were prognostic factors for overall survival. Multivariate analysis showed that the 2002 AJCC TNM stage (P < 0.001) was the only independent prognostic factor for survival. The value of the area under the receiver operator characteristic (ROC) curve (AUC) of the 2002 AJCC TNM staging system was larger than that of VALSG staging system with regard to predicting overall survival (0.774 vs. 0.620). None of the single treatment regimens showed any benefit for survival by Cox regression analysis. Thus, the 2002 AJCC TMN staging system improved the prediction of SCCE prognosis; however, the optimal treatment regimen for SCCE remains unclear.

Treatment of pulmonary neuroendocrine tumours: state of the art and future developments.

The current classification of pulmonary neuroendocrine tumours includes four subtypes: low-grade typical carcinoid tumour (TC), intermediate-grade atypical carcinoid tumour (AC), and two high-grade malignancies: large cell neuroendocrine carcinoma and small cell lung cancer (SCLC). Unfortunately, with the exclusion of SCLC, no large phase II and III trials for pulmonary neuroendocrine tumours have been published. Thus, several treatment approaches are available for their treatment but none of them has been validated in appropriately designed and adequately sized clinical trials. The main problem of the published studies is that they include neuroendocrine tumours from various sites of origin with different clinical behaviour. It is important that future studies consider these tumours separately. In this regard, increased awareness and referral of these patients to tertiary centres, in which a multidisciplinary management is available, may be of value. The aim of this review is to evaluate the state of the art and discuss future developments in the management of pulmonary neuroendocrine tumours excluding SCLC which we consider should be addressed in a different issue.

[Diagnostics of lung cancers becoming more precise]. / Keuhkosyöpien tarkentuva diagnostiikka.

Nearly half of all lung cancers are adenocarcinomas falling into various subtypes. Other common types of lung cancer include squamous cell carcinoma and small cell carcinoma. The pathogenesis and molecular biology of lung cancer has been the subject of considerable research over the last few years, and new pharmacologic therapies have been developed. The histological classification of lung adenocarcinomas has been revised in 2011, and is already becoming established in replacing the WHO classification. The aim of the new classification is to make the diagnostics of lung cancer and assessment of treatment options more precise.

The morphological and molecular diagnosis of lung cancer.

BACKGROUND: In Germany, lung cancer causes more deaths than any other malignant disease. Its main etiology is smoking, but other risk factors need to be considered as well. The morphological, molecular and biological phenotype is complex and should no longer be just categorized as either small-cell or non-small cell lung cancer. METHODS: This review article is based on the authors' longstanding involvement in the scientific investigation and diagnostic evaluation of lung cancer, including contributions to the current WHO classification and collaboration in the new interdisciplinary classification of adenocarcinoma. The relevant literature was selectively reviewed. RESULTS: Lung cancer is morphologically classified into four main subtypes-small-cell carcinoma, squamous-cell carcinoma, adenocarcinoma, and large-cell carcinoma. Genetic and molecular analyses have revealed distinct differences within subtypes; in particular, adenocarcinomas can be further subdivided. Complex techniques of genomic analysis are now available, but clinicopathological data are still the most important determinants of prognosis and are clearly better for this purpose than molecular classification alone. Nonetheless, the assessment of specific molecular markers is becoming increasingly important. CONCLUSION: The morphological and molecular classification of lung cancer is undergoing a re-evaluation which will lead to more accurate assessment of individual prognoses and to improved prediction of the response to specific treatment regimens.

Borderline ovarian mucinous neoplasm recurring as small cell carcinoma of hypercalcemic type: evidence for an epithelial histogenesis and relationship with ovarian mucinous tumors for this enigmatic neoplasm.

Ovarian small cell carcinoma of hypercalcemic type (OSCCHT) is an uncommon neoplasm of uncertain histogenesis. As far as we are aware, this neoplasm has never been reported in association with another primary ovarian tumor. We report a case in a 33-year-old patient in whom an extraovarian pericolonic neoplasm with the morphological features and immunohistochemical profile of OSCCHT developed 5 years after removal of an ovarian mucinous borderline tumor of the intestinal type. Together with the observation that mucinous epithelium is seen in some OSCCHTs, this case raises the possibility that this enigmatic neoplasm is of epithelial origin and is related to primary ovarian mucinous neoplasms. The pericolonic tumor exhibited an unusual immunophenotype with positive staining with CD99 and FLI-1, suggesting the possibility of a neoplasm in the Ewing family of tumors. This was excluded by molecular studies that showed no evidence of EWS/FLI-1 or EWS/ERG translocation.