Large cell neuroendocrine carcinoma (LCNEC) is a neuroendocrine carcinoma (NEC) of the lung that is characterized by its heterogeneous morphology, diverse immunophenotypes, and complex genomic profile Show more
Large cell neuroendocrine carcinoma (LCNEC) is a neuroendocrine carcinoma (NEC) of the lung that is characterized by its heterogeneous morphology, diverse immunophenotypes, and complex genomic profiles. Among LCNECs, a subset expressing the transcription factor POU2F3 (LCNEC-P) has been suggested to share similarities with small cell lung carcinoma (SCLC)-P, a subtype of SCLC defined by POU2F3 expression. However, the specific characteristics of LCNEC-P have not been fully elucidated. Therefore, the aim of the present study is to clarify the clinicopathological, immunohistochemical, and genetic characteristics of LCNEC-P. Fifty-six LCNEC cases were analyzed, including 12 LCNEC-P and 44 LCNEC-non-P cases. Morphologically, LCNEC-P exhibited significantly lower cytomorphology scores, indicating a resemblance to SCLC. Immunohistochemically, LCNEC-P showed the lower expression of neuroendocrine markers (SYP, CHGA, and INSM1), but the higher expression of C-MYC than LCNEC-non-P. A strong mutually exclusive expression pattern was observed between POU2F3 and ASCL1/NEUROD1. Whole-genome sequencing of 20 cases revealed that LCNEC-P harbored RB1 mutations in 100 % of cases, which was significantly higher than in LCNEC-non-P (40 %). FGFR1 amplification was observed in 60 % of LCNEC-P cases, representing a higher prevalence than previously reported for LCNEC. In addition, LCNEC-P showed a distinct copy number alteration profile, including frequent 20q13 amplification, compared with LCNEC-non-P. These results demonstrate that LCNEC-P represents a distinct subgroup of LCNEC that is characterized by a specific morphological, immunohistochemical, and genetic profile, closely resembling SCLC-P. This study provides insights into the biology of LCNEC-P and supports its classification as a unique entity within LCNEC. Show less
Primary haematological neoplasms of the larynx are uncommon; therefore, information regarding their epidemiology is limited and the diagnosis of histological types requires careful consideration. The Show more
Primary haematological neoplasms of the larynx are uncommon; therefore, information regarding their epidemiology is limited and the diagnosis of histological types requires careful consideration. The current study describes the case of a 72-year-old male patient with primary laryngeal lymphoplasmacytic lymphoma (LPL) that was difficult to distinguish from plasmacytoma. Imaging examinations of the neck revealed a mass in the right laryngeal folds, 25×12×25 mm in size, which was surgically resected by direct laryngoscopy. Histopathologically, the mass showed diffuse proliferation of plasma cells with CD138 (+) and IgG (+) in the submucosal stroma. Flow cytometry revealed the tumour was positive for CD19 and negative for CD56. Based on these findings, the final diagnosis was confirmed as LPL, albeit similar to plasmacytoma regarding phenotypic features. There was no evidence of local or systemic recurrence following surgery, and the patient has been followed up without additional treatment. This case highlights the unique presentation of laryngeal lymphoma mimicking solitary plasmacytoma. The key factor in the diagnosis was the expression pattern of surface antigen markers. Show less