Schwannoma arising in a lymph node mimicking metastatic pulmonary carcinoma

Primary lipoblastic nerve sheath tumor in an inguinal lymph node mimicking metastatic tumor: a case report and literature review

Lipoblastic nerve sheath tumors of soft tissue are characterized as schwannoma tumors that exhibit adipose tissue and lipoblast-like cells with signet-ring morphology. They have been documented to arise in various anatomic locations, including the thigh, groin, shoulder, and retroperitoneum. However, to our knowledge, this tumor has not been previously reported as a lymph node primary. We present herein the first case of a benign primary lipoblastic nerve sheath tumor arising in an inguinal lymph node in a 69-year-old man. Microscopic examination revealed a multinodular tumor comprising fascicles of spindle cells, as well as adipocytic and lipoblast-like signet-ring cell component in the context of schwannoma. Despite the presence of some bizarre cells with nuclear atypia, no obvious mitotic activity or necrosis was observed. Immunohistochemical analysis showed strong and diffuse expression of S-100, SOX10, CD56, and NSE in the spindle cells as well as in the signet-ring lipoblast-like cells and the mature adipocytes. Sequencing analysis of the neoplasm identified six non-synonymous single nucleotide variant genes, specifically NF1, BRAF, ECE1, AMPD3, CRYAB, and NPHS1, as well as four nonsense mutation genes including MRE11A, CEP290, OTOA, and ALOXE3. The patient remained alive and well with no evidence of recurrence over a period of ten-year follow-up.

Schwannoma arising in mediastinal lymph node diagnosed by endobronchial ultrasound

Schwannoma is a peripheral nerve sheath tumour that largely originates from the posterior mediastinum. Schwannoma arising in mediastinal lymph node is extremely rare. A 53-year-old female was referred to our hospital for the evaluation of enlarged mediastinal lymph node. Computed tomography scan revealed a non-enhancing soft tissue mass at Rt. paratracheal area. Endobronchial ultrasound showed a well-defined round-shaped lymph node and transbronchial needle aspiration was performed from this lymph node. Pathologic findings revealed spindle cells with strong S100 positivity. Complete surgical excision was done. We report a rare case of schwannoma arising in mediastinal lymph node diagnosed by endobronchial ultrasound.