Malignant peripheral nerve sheath tumor: a clinicopathological analysis / 中华病理学杂志

Objective: To investigate the clinicopathological, immunophenotypic, and genetic features of malignant peripheral nerve sheath tumor (MPNST). Methods: Twenty-three cases of MPNST were diagnosed at the Jiangsu Province Hospital (the First Affiliated Hospital of Nanjing Medical University), China, between January 2012 and December 2022 and thus included in the study. EnVision immunostaining and next-generation sequencing (NGS) were used to examine their immunophenotypical characteristics and genomic aberrations, respectively. Results: There were 10 males and 13 females, with an age range of 11 to 79 years (median 36 years), including 14 cases of neurofibromatosis type I-associated MPNST and 9 cases of sporadic MPNST. The tumors were located in extremities (7 cases), trunk (4 cases), neck and shoulder (3 cases), chest cavity (3 cases), paraspinal area (2 cases), abdominal cavity (2 cases), retroperitoneum (1 case), and pelvic cavity (1 case). Morphologically, the tumors were composed of dense spindle cells arranged in fascicles. Periphery neurofibroma-like pattern was found in 73.9% (17/23) of the cases. Under low magnification, alternating hypercellular and hypocellular areas resembled marbled appearance. Under high power, the tumor cell nuclei were irregular, presenting with oval, conical, comma-like, bullet-like or wavy contour. In 7 cases, the tumor cells demonstrated marked cytological pleomorphism and rare giant tumor cells. The mitotic figures were commonly not less than 3/10 HPF, and geographic necrosis was often noted. Immunohistochemically, tumor cells were positive for S-100 (14/23, 60.9%) and SOX10 (11/23, 47.8%). The loss of the CD34-positive fibroblastic network encountered in neurofibromas was observed in 14/17 of the MPNST cases. The loss of H3K27me3 expression was observed in 82.6% (19/23) of the cases. Moreover, SDHA and SDHB losses were presented in one case. NGS revealed that NF1 gene loss of function (germline or somatic) were found in all 5 cases tested. Furthermore, four cases accompanied with somatic mutations of SUZ12 gene and half of them had somatic mutations of TP53 gene, while one case with germline mutation in SDHA gene and somatic mutations in FAT1, BRAF, and KRAS genes. Available clinical follow-up was obtained in 19 cases and ranged from 1 to 67 months. Four patients died of the disease, all of whom had the clinical history of neurofibromatosis type Ⅰ. Conclusions: MPNST is difficult to be differentiated from a variety of spindle cell tumors due to its wide spectrum of histological morphology and complex genetic changes. H3K27me3 is a useful diagnostic marker, while the loss of CD34 positive fibroblastic network can also be a diagnostic feature of MPNST. NF1 gene inactivation mutations and complete loss of PRC2 activity are the common molecular diagnostic features, but other less commonly recurred genomic aberrations might also contribute to the MPNST pathogenesis.

Primary hepatic angiosarcoma: a clinicopathological analysis of nine cases / 中华病理学杂志

Objective: To investigate the clinical manifestations, histomorphology, and differential diagnosis of primary hepatic angiosarcoma. Methods: Nine cases of primary hepatic angiosarcoma diagnosed in the Department of Pathology, the First Affiliated Hospital of Nanjing Medical University from January 2014 to December 2021 were collected, including biopsy and surgical specimens. The histomorphology, clinical, and radiologic findings were analyzed. The relevant literature was also reviewed. Results: There were six males and three females, aged 30 to 73 years (mean 57 years). Grossly, the growth pattern of the tumor was classified as either mass formation or non-mass formation (sinusoidal). Microscopically, the mass-forming primary hepatic angiosarcoma were further subdivided into vasoformative or non-vasoformative growth patterns; and those non-vasoformative tumors had either epithelioid, spindled, or undifferentiated sarcomatoid features. Sinusoidal primary hepatic angiosarcoma on the other hand presented with markedly dilated and congested blood vessels of varying sizes, with mild to moderately atypical endothelial cells. Follow-up in all nine cases revealed 8 mortality ranging from 1 to 18 months (mean 5 months) from initial diagnosis. One patient was alive with disease within a period of 48 months. Conclusions: Primary hepatic angiosarcoma is a rare entity with a wide spectrum of histomorphology, and often misdiagnosed. It should be considered when there are dilated and congested sinusoids, with overt nuclear atypia. The overall biological behavior is aggressive, and the prognosis is worse.