Even though the diagnosis of schwannoma is usually straightforward in lesions with classic features, tumors with predominantly epithelioid morphology or marked myxoid change may present a diagnostic challenge. There are relatively few reported cases of epithelioid schwannoma entirely lacking classic morphology, and these have occurred in subcutaneous tissues, mucosal surfaces, or as gastrointes...

Rhabdomyoblastic differentiation in a malignant peripheral nerve sheath tumor (MPNST) is termed malignant triton tumor (MTT), a rare neoplasm that poses a diagnostic dilemma in the differential diagnosis of neck masses and portends poor prognosis. We report a sporadic case of MTT of the neck in a 23-year-old female. We present the pathological findings. Immunohistochemistry confirmed the neurog...

Malignant peripheral nerve sheath tumor is a rare tumor occurring in 5%-10% of all malignant soft tissues sarcomas and triton tumor arising from neurofibromatosis type 1 (NF-1) is even rarer with associated high rate of mortality. No case of triton tumor has been reported in Nigeria to the best of our knowledge. We seek to report a case of lately detected retroperitoneal triton tumor presenting...

1. Macarenco RS, Ellinger F, Oliveira AM. Perineurioma: a distinctive and underrecognized peripheral nerve sheath neoplasm. Arch Pathol Lab Med 2007;131:625-36. 2. Hornick JL, Fletcher CD. Intestinal perineuriomas: clinicopathologic definition of a new anatomic subset in a series of 10 cases. Am J Surg Pathol 2005;29:859-65. 3. Gupta K, Dey P, Vashisht R. Fine-needle aspiration cytology of mali...

A 38-year-old man was diagnosed with malignant peripheral nerve sheath tumour of the maxilla. He was treated with total maxillectomy. Histopathological examination of the resected specimen revealed a close resection margin. The tumour was of high grade with an MIB-1 labelling index of almost 60%. At six weeks following the surgery, he developed local tumour relapse. The patient succumbed to the...

Malignant triton tumors are a rare subtype of malignant peripheral nerve sheath tumors showing rhabdomyosarcomatous differentiation. We report the case of a 33-year-old patient who underwent an excision of such a tumor by thoracic and cardiac surgery. He was reoperated on 1 month later because of a tumor of the small intestine and received adjuvant radiation.

Malignant peripheral nerve sheath tumors (MPNST) are incurable tumors of the Schwann cell lineage that progress unpredictably from benign plexiform neurofibromas. In this issue of Cancer Discovery, Watson and colleagues use an insertional mutagenesis screen combined with network analysis to identify the canonical WNT signaling pathway as an important potential biomarker of tumor progression and...

A 14-year-old male Siberian tiger (Panthera tigris altaica) was admitted with an ulcerating mass on the right thoracic wall. Radiographic and computed tomographic evaluation indicated 2 isolated cutaneous masses without any signs of metastasis. Histology of a Tru-Cut biopsy revealed an anaplastic sarcoma with giant cells. Both tumors were resected with appropriate normal tissue margins. The siz...

Neurofibromatosis 1 predisposes affected individuals to the development of benign and malignant tumours that are frequently disfiguring and difficult to manage. However, advances in molecular biology and the development of mouse models have facilitated our understanding of disease pathogenesis. Positron emission tomography has demonstrated that sophisticated imaging techniques have a role in di...

A 26-year-old man with neurofibromatosis type 1 (NF1) presented with a giant malignant schwannoma of the sciatic nerve. The differential diagnosis of malignant peripheral nerve sheath tumor (MPNST) was based on clinical, radiological, and histological evidence. The tumor apparently originated in a spinal plexiform neurofibroma. The lesion was resected totally without neural damage to the sciati...