Primary MiNEN of the urinary bladder: an hitherto undescribed entity composed of large cell neuroendocrine carcinoma and adenocarcinoma with a distinct clinical behavior : Description of a case and review of the pertinent literature

Mixed neuroendocrine-nonneuroendocrine epithelial neoplasm of muscle invasive bladder cancer: a clinicopathologic case study

Mixed neuroendocrine-nonneuroendocrine epithelial neoplasms are rare malignant neoplasms that may occur in the bladder with highly aggressive behavior. Because of its worse prognosis, when compared to the pure urothelial carcinoma without the neuroendocrine component, the bladder mixed neuroendocrine-nonneuroendocrine epithelial neoplasm may be considered a distinct clinicopathologic entity. We present a case of mixed neuroendocrine-nonneuroendocrine epithelial neoplasm occurring in the urinary bladder of an elderly female with a personal history of chronic kidney disease, drug-resistant urinary tract infections, and neurogenic bladder. Her presenting symptoms included complaints of abdominal pain, urinary urgency, oliguria, dysuria, and occasional hematuria. Recognition of the clinicopathologic features of these rare aggressive neoplasms is important for accurate early diagnosis, necessitating appropriate therapeutic management.

Ureter mixed neuroendocrine-non-neuroendocrine neoplasm: a case report and literature review

Cases of mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) of the urinary system are rare, and reports of primary MiNENs in the ureter are lacking. Herein, we present the case of a 71-year-old man who presented with painless gross hematuria and weight loss. Contrast-enhanced abdominal computed tomography (CT) revealed a tumor, comprising small cell neuroendocrine carcinoma (SCNEC) and adenocarcinomatous components, attached to the ureter. The SCNEC components were strongly positive for synaptophysin, CD56 and INSM1 and adenocarcinomatous components were strongly positive for CDX2 and cytokeratin 20, respectively. Four weeks post-surgery, the patient received four cycles of cisplatin-based chemotherapy; the 7-month follow-up CT confirmed that he was healthy without disease recurrence. The occurrence of MiNEN in the ureter with SCNEC and adenocarcinomatous components is extremely rare, wherein histopathological and immunohistochemical features aid in the diagnosis MiNEN. With its aggressive nature, MiNEN can only be effectively treated by early diagnosis and radical surgery.

Primary pure large cell neuroendocrine carcinoma of the urinary bladder: a case report and literature review

Background

The large cell neuroendocrine carcinoma (LCNEC) of the urinary bladder is a rare malignancy. With its high aggressiveness and poor prognosis, the disease is often accompanied by metastasis or recurrence. The lack of specific clinical manifestations and imaging features causes considerable challenges for clinical diagnosis and treatment.

Case presentation

We report a case of LCNEC of the urinary bladder. The patient was a 79-year-old male admitted to our hospital with recurrent episodes of asymptomatic gross hematuria. Based on the computed tomography (CT) scan findings, our patient presented with a bladder mass displaying invasion into the serosal layer, suggestive of muscle involvement and indicative of malignancy. The patient received a radical cystectomy, and the postoperative pathology confirmed primary, pure LCNEC of the urinary bladder. We gave him 16 cycles of toripalimab immunotherapy. As of follow-up, the patient was alive, and periodic CT reexamination showed no evidence of recurrence.

Conclusions

We reviewed domestic and foreign literature and found no explicit treatment protocols exist for the disease. Surgical resection combined with chemotherapy were the most common treatments. Herein, we reported the first case of primary, pure LCNEC of the urinary bladder treated by radical cystectomy combined with pure immunotherapy, achieving sustained remission, which provides a new idea for the immunotherapy and integrative treatment of the disease.

Mixed Neuroendocrine/Non-neuroendocrine Neoplasm (MiNEN) of the Ovary Arising from Endometriosis: Molecular Pathology Analysis in Support of a Pathogenetic Paradigm

Primary ovarian neuroendocrine neoplasms (Ov-NENs) are infrequent and mainly represented by well-differentiated forms (neuroendocrine tumors - NETs - or carcinoids). Poorly differentiated neuroendocrine carcinomas (Ov-NECs) are exceedingly rare and only few cases have been reported in the literature. A subset of Ov-NECs are admixed with non-neuroendocrine carcinomas, as it occurs in other female genital organs, as well (mostly endometrium and uterine cervix), and may be assimilated to mixed neuroendocrine/non-neuroendocrine neoplasms (MiNENs) described in digestive and extra-digestive sites. Here, we present a case of large cell Ov-NEC admixed with an endometrioid carcinoma of the ovary, arising in the context of ovarian endometriosis, associated with a uterine endometrial atypical hyperplasia (EAH). We performed targeted next-generation sequencing analysis, along with a comprehensive immunohistochemical study and FISH analysis for TP53 locus, separately on the four morphologically distinct lesions (Ov-NEC, endometrioid carcinoma, endometriosis, and EAH). The results of our study identified molecular alterations of cancer-related genes (PIK3CA, CTNNB1, TP53, RB1, ARID1A, and p16), which were present with an increasing gradient from preneoplastic lesions to malignant proliferations, both neuroendocrine and non-neuroendocrine components. In conclusion, our findings underscored that the two neoplastic components of this Ov-MiNEN share a substantially identical molecular profile and they progress from a preexisting ovarian endometriotic lesion, in a patient with a coexisting preneoplastic proliferation of the endometrium, genotypically and phenotypically related to the ovarian neoplasm. Moreover, this study supports the inclusion of MiNEN in the spectrum ovarian and, possibly, of all gynecological NENs, among which they are currently not classified.

The classification of neuroendocrine neoplasms of the breast and its clinical relevance

Neuroendocrine neoplasms of the breast (Br-NENs) are rare tumors of the mammary gland. Their definition and classification have been a matter of discussion for more than half a century, as they present some degree of overlap with other malignancies in the mammary gland. The recent evolutions in the understanding of the pathogenesis of neuroendocrine neoplasms (NENs) as well as the novel tools in the diagnostic arsenal of the pathologists, and a better correlation with clinical data, have led to improved classification schemes for these entities, beginning from those arising in digestive and thoracic organs. These new classification concepts have been recently expanded to NENs arising in every anatomical site, with the proposal of a common classification framework that has been applied in the 5th edition of the WHO classification of tumors. These concepts include the recognition of two distinct families of NENs (neuroendocrine tumors, NETs, and neuroendocrine carcinomas, NECs), the identification of mixed neuroendocrine/non-neuroendocrine neoplasms, and the application of definite morphological and immunohistochemical criteria for the diagnosis of NENs. The last WHO classification of Br-NENs, however, still seems to leave several unanswered questions and unmet needs in the understanding of diagnostic and clinical features of these entities. This review will critically revise the current classification of Br-NENs, underlining its lights and shadows and focusing on the identification of diagnostic histopathological criteria that can help the univocal recognition of Br-NET, Br-NEC, and Br-MiNEN.