Objective:To explore the clinicopathological features of end-stage lung disease complicated with neuroendocrine carcinoma after lung transplantation (LT).Methods:From April 2017 to December 2021, 5 cases of neuroendocrine cancer were diagnosed as end-stage lung disease by hematoxylin-eosin (HE) and immunohistochemical stain.Clinical follow-up data, histological characteristics and immunophenotyping were analyzed retrospectively.Results:The ratio of male-to-female in five recipients was 4: 1 and the average age 64(56-73) years.Three cases were idiopathic pulmonary fibrosis concomitant with small cell carcinoma (including 1 case of combined small cell carcinoma), bronchiectasis plus carcinoid carcinoma (n=1) and connective tissue disease-related fibrosis plus carcinoid carcinoma (n=1). HE stain indicated that morphological spectrum changed from neuroendocrine cell hyperplasia to carcinoid in transplanted lung of bronchiectasis.Immunohistochemical stain indicated that neuroendocrine markers CgA, Syn, CD56 and epithelial markers AE1/AE3, TTF-1 were positive for small cell carcinoma and carcinoid.Ki-67 index of small cell carcinoma (n=2) and combined small cell carcinoma (n=1) was 80% and Ki-67 index of carcinoid (n=2) was ≤1%.Until the last follow-up, 3/5 patients survived and the remaining 2 died of Klebsiella pneumoniae, Corynebacterium striatus and Acinetobacter baumannii infections at Days 33 and 196 post-transplantation.Conclusions:Neuroendocrine carcinoma in transplanted lung is more common in elderly males and end-stage lung disease is mostly idiopathic pulmonary fibrosis.Small cell carcinoma is a major type of neuroendocrine carcinoma.Specific neuroendocrine markers and TTF-1 aid in a definite diagnosis of neuroendocrine carcinoma.Postoperative infection is an important prognostic factor.

Objective:To investigate the clinicopathological features and prognostic factors of primary mediastinal large B-cell lymphoma (PMBL).Methods:The clinical data of 60 patients with PMBL including 44 biopsy cases and 16 consultation cases from September 2000 to November 2019 in the Department of Pathology, China-Japan Friendship Hospital (14 cases) and Peking Union Medical College Hospital (46 cases) were enrolled. Pathologic features, immunophenotype, immunoglobulin (Ig) gene rearrangement and microRNA expression profile were retrospectively studied.Results:Of the 60 patients, 23 were males and 37 were females, age ranged from 15 to 64 years (median 28 years). Immunohistochemical staining showed that the tumor cells were positive for pan-B cell antigens, CD30 (77.4%, 24/31), CD23 (73.1%, 19/26), MUM1 (45.8%, 11/24), Ki-67 index ≥70 % (90.6%, 29/32). EBER in situ hybridization was analyzed in 21 PMBL, only one case (4.8%) was positive. Ig gene rearrangement was performed in 20 cases, and seven were positive (35.0%). MicroRNA gene expression profiles were analyzed in seven cases of PMBL and nine cases of diffuse large B-cell lymphoma, and there were 33 microRNAs with significant difference ( P<0.05). Univariate analysis indicated that the poor prognostic factors included serum lactate dehydrogenase (LDH) level,International Prognostic Index (IPI) score ≥3, stages Ⅲ-Ⅳ, chemotherapy not combined with rituximab and MUM1 positivity ( P<0.05). Multivariate analysis showed that the treatment combined with rituximab was independently related to prognosis ( P<0.05). Conclusions:PMBL is different from diffuse large B-cell lymphoma in clinicopathologic features, immunophenotypic presentation and molecular features. The prognostic factors, molecular genetics and immunological characteristics reveal that this study has enriched our understanding of the biology of PMBL, thus providing evidence and strategies for treatment.