![]() ![]() We report 4 rare cases of spindle cell variant of MTC. Immunohistochemistry showed that the tumor cells were positive for calcitonin, chromogranin A, synaptophysin, CD56, and TTF-1, but negative for other lineage-specific markers. Histologically, the tumors showed spindle shaped cells in bundles or interlaced arrangement, separated by hyalinised fibrous stroma that contained amyloid deposits. Three patients underwent total thyroidectomy and regional lymph node dissection, and 1 patient underwent thyroid mass resection. Ultrasound showed solid and hypoechoic nodules. Here we describe 4 cases of spindle cell variant of MTC collected from 2012 to 2019. Among them, spindle cell variant is extremely rare. More than 14 histological variants have been described. It accounts for about 10% of all thyroid malignancies. Overall, the findings are consistent with malignant peripheral nerve sheath tumor.Medullary thyroid carcinoma (MTC) is a malignant tumor derived from C cells. Negative stains include EMA, CK AE1 / AE3, desmin, SMA, MART1, MUC4, CD56, neurofilament and ER. The remainder of the lesion is has focal S100 reactivity. This portion of the lesion shows immunoreactivity for S100 and CD34. The periphery of the lesion is relatively hypocellular with a single area composed of cytologically bland spindle cells, which morphologically resembles neurofibroma (slide A3). Mitotic activity is present in up to 7/10 high power fields and no necrosis is identified. It is composed of variably pleomorphic spindle cells forming fascicles and storiform structures with a marbling pattern. Comment: Histologic sections contain a dermal based neoplasm with a plexiform architectural pattern.Tumor size: 3.8 cm in greatest dimension, per outside report.Spindle cell sarcoma, consistent with malignant peripheral nerve sheath tumor (see comment).Right hand mass, excision (consult case):.MPNST, high grade: MPNST with at least 10 mits/10 HPF or 3 - 9 mits/10 HPF combined with necrosis ( Hum Pathol 2017 67:1).MPNST, low grade: features of ANNUBP but with mitotic index of 3 - 9/10 HPF and no necrosis.At least 2 of the following features: cytologic atypia, loss of neurofibroma architecture, hypercellularity, > 1/50 HPF and Atypical neurofibromatous neoplasm of uncertain biologic potential (ANNUBP):.Proposed nomenclature for the spectrum of NF1 associated nerve sheath tumors:. ![]() Glandular elements are exceedingly rare ( Int J Surg Pathol 2017 25:310).Heterologous differentiation may include chondrosarcomatous, osteosarcomatous and rhabdomyosarcomatous components (malignant triton tumor).Precursor lesion, such as neurofibroma, may be identifiable.Can have foci of myxoid stroma and hyalinization.May have uniform cellularity with fibrosarcoma-like fascicular growth, raising the differential diagnosis of synovial sarcoma.Uniform spindle cells with hyperchromatic, thin, wavy, or focally buckled nuclei.Low power: marbled appearance due to alternating hypocellular and hypercellular areas with perivascular accentuation.Has been associated with adverse clinical behavior ( Eur J Surg Oncol 2013 39:46).MPNST with heterologous rhabdomyoblastic differentiation (Malignant Triton tumor).Distinct molecular features from conventional MPNSTs and harbor SMARCB1 gene inactivation and INI1 loss in up to 40 - 67% of cases ( Am J Surg Pathol 2019 43:835, Histopathology 2016 68:286, Am J Surg Pathol 2015 39:673).Typically have diffuse and strong expression of S100 and SOX10 ( Am J Surg Pathol 2019 43:835).Rare cases may arise in epithelioid Schwannoma.Rare subtype, usually not associated with NF1 ( Am J Surg Pathol 2019 43:835).In the absence of association with NF1 or radiation, diagnosis is challenging and based on histologic and immunohistochemical features suggesting Schwannian differentiation ( Am J Surg Pathol 2016 40:896).May arise from a preexisting nerve sheath tumor in neurofibromatosis type 1 (NF1) or in the setting of prior radiation therapy.Malignant neoplasm arising from peripheral nerve. ![]()
0 Comments
Leave a Reply. |