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Merkel Cell Carcinoma
Published in Debjani Sahni, Adam Lerner, Bilal Fawaz, Advanced Skin Cancer, 2022
Allene S. Fonseca, Song Park, Paul Nghiem
Clinical findings in MCC are relatively non-specific. The neoplasm presents as a pink-violaceous, erythematous, indurated nodule, often with associated tenderness and rapid growth.1 The neoplasm arises on the head and neck in the majority of patients >65 years of age, whereas it favors the trunk in younger individuals.3 Mucosal and metastatic MCCs with no known primary are exceedingly rare but have been reported.9,10 Histologic features include sheets of small, round, basaloid cells with a “salt and pepper” chromatin pattern and numerous mitotic figures.11 Positive staining with cytokeratin-20 (CK-20) and neurofilament supports the diagnosis, whereas negative staining with thyroid transcription factor-1 (TTF-1) is essential to rule out metastatic small cell lung carcinoma.11 CK-7 is generally negative but can be positive in a minority of cases.11
Bronchopulmonary and thymic carcinoids; other endocrine tumors
Published in Demetrius Pertsemlidis, William B. Inabnet III, Michel Gagner, Endocrine Surgery, 2017
Leslie James, Andrea Wolf, Raja Flores
SLCL is sometimes referred to as “oat cell carcinoma” because the neoplastic cells resemble oat grains. The cells appear round or somewhat fusiform, with an extremely high nuclear-to-cytoplasmic ratio. In most cases, the cytoplasm is nearly imperceptible. The nucleus contains uniformly dispersed fine or stippled “salt and pepper” chromatin, and inconspicuous nucleoli. Nucleoli may be obscured when nuclei are particularly hyperchromatic. Mitoses are generally abundant, but they may also be partially obscured by hyperchromasia. Cells may coalesce around blood vessels, forming a “pseudorosette.” “Cushing” phenomenon, the distortion of groups of cells that coalesce and smear, and necrosis are both characteristic of SCLC [20]. SCLC may be associated with various paraneoplastic syndromes, including hyponatremia due to the syndrome of inappropriate antidiuretic hormone (SIADH), Cushing syndrome due to ectopic ACTH production, and Eaton–Lambert syndrome due to autoantibodies affecting the voltage-gated calcium channels in the presynaptic membranes of the neuromuscular junction.
Ocular adnexal manifestations of neuroendocrine neoplasms: a case report and a major review
Published in Orbit, 2021
Alexander J. Hatsis, Roger K. Henry, Mark T. Curtis, Jurij R. Bilyk, Meera D. Sivalingam, Ralph C. Eagle, Tatyana Milman
Histopathology revealed a neoplasm composed of packeted (“organoid”) nests of cells with round to ovoid nuclei, minimal nuclear pleomorphism, finely granular (“salt and pepper”) chromatin, inconspicuous nucleoli, and abundant eosinophilic cytoplasm (Figure 1C). No necrosis was present. Rare mitoses were identified in tumor cells and the mitotic rate was 1 mitosis per 10 high power fields. Immunohistochemical stains showed positivity for neuroendocrine markers synaptophysin, chromogranin (Figure 1D), neuro-specific enolase (NSE), and CD56, and cytokeratins (CAM5.2) The Ki-67 proliferation index was 6.7% as determined by Aperio ® Digital Pathology (Leica Biosystems, Wetzlar, Germany) analysis of 317,188 cells (Figure 1Dinset). The combined morphologic and immunohistochemical findings were supportive of the diagnosis of a well-differentiated NEN/typical carcinoid tumor, likely metastatic.
Current and future therapeutic approaches for the treatment of small cell lung cancer
Published in Expert Review of Anticancer Therapy, 2018
Antonio Rossi, Rebecca Tay, Jaseela Chiramel, Arsela Prelaj, Raffaele Califano
SCLC was previously known as ‘oat cell carcinoma’ due to its oval shape and resemblance to oat granule. In 1988, International Association for the study of Lung Cancer (IASLC) replaced the term oat cell with SCLC. The diagnosis of SCLC is primarily based on light microscopy. The tumor cells usually measure less than the diameter of three small resting lymphocytes. Microscopic appearances are clusters or sheets of round small cells with scanty cytoplasm, indistinct nucleoli, salt and pepper chromatin without prominent clumps and frequent mitosis. Stroma is scanty, vascular, and delicate. Large areas of necrosis are frequently seen. The mitotic rate is characteristically high averaging 60–80 per 2 mm2. Crush artifact is a frequent finding and it can make the interpretation difficult. In surgically resected specimen, the tumor cell achieves better fixation and the cells of small cells appear larger than in small biopsies. In the 2015 World Health Organization (WHO) Classification of Tumors of the Lung, Pleura, Thymus and Heart, the carcinoid tumors, SCLC and large cell neuroendocrine carcinoma (LCNEC) were grouped together. The tumors are listed in the order of their frequency with SCLC first as it is the most common [4]. The term combined SCLC is used when a component of NSCLC including adenocarcinoma, squamous carcinoma, large cell carcinoma is present in the specimen. In resected specimens, combined SCLC may occur in up to 28% of cases [5]. In complex cases, immunohistochemistry (IHC) stains are helpful. A high proliferation rate (Ki67) of 80–100% is seen in SCLC. Thyroid transcription factor-1 (TTF-1) is positive in 70–80% of cases, but it is not useful in determining the primary site of small cell carcinoma as it can be positive in extra-pulmonary carcinoma as well. SCLC is characterized by the presence of tumor suppressor genes TP53 (75–90%) and RB1 mutations (60–90%). TP53 and RB1 genes are frequently inactivated by chromosomal deletions and loss-of-function mutations. Recurrent losses of chromosome arms 1p, 3p, 5q, 17p have also been observed [6].