What is the outcome for spindle cell melanoma?Īlthough the tendency for nodal involvement is low, the majority of spindle cell melanomas present with advanced disease, with a worse prognosis being seen in Caucasian men aged over 66 years. Surgical excision is the first step in management. The treatment for spindle cell melanoma is similar to that for other forms of melanoma. What is the treatment for spindle cell melanoma? S100 and HMB-45 are usually negative after staining.Cytokeratin stains such as 34betaE12 are positive in spindle-cell squamous cell carcinoma.CD34 is positive in dermatofibrosarcoma protuberans.HMB-45 and Melan-A are negative in peripheral nerve sheath tumours.The markers S100, CD34, and GAP43 are positive after staining in peripheral nerve sheath tumours.The markers S100 and HMB-45 are negative after staining.The markers S100, p75, and HMB-45 are negative after staining in atypical fibroxanthoma. The markers S100, p75, or HMB-45 are negative after staining.Smooth-muscle actin (SMA) stain is positive in leiomyosarcoma.Leiomyosarcoma pathology may be indistinguishable morphologically from melanoma. The stroma tends to be hyalinised, sclerotic, and reticulated. Cutaneous clear-cell sarcoma tends to show uniform patterns of spindle-cell fascicles (bundles) under microscopy, which are present throughout an entire tumour and encased by fibrous septa. The differentiation of cutaneous clear cell sarcoma from spindle cell melanoma is largely histological, as both may stain positively for the same indicators: S100, HMB-45, and Melan-A. The architecture is symmetrical with good lateral demarcation, epidermal hyperplasia, and uniform nests of cells. Reed naevus (also called a pigmented spindle-cell naevus) is a melanocytic naevus with a largely spindle-cell appearance under microscopy. HMB-45, laminin T, laminin NT, Melan-A, and c-KIT are negative in desmoplastic melanoma.Collagen IV, CD68, MDM2, and trichrome are positive after staining in desmoplastic melanoma.Melanomas with both spindle cell and desmoplastic components at varying levels between 10% and 90% are referred to as mixed variants.When > 90% of a tumour is composed of desmoplastic cells, a diagnosis of desmoplastic melanoma is made.When spindle cells represent > 90% of a tumour, a diagnosis of spindle cell melanoma is made.Recent studies now suggest that desmoplastic melanoma and spindle cell melanoma represent two distinct types of melanoma, as differences in staining, genetic mutations, and clinical manifestations have been found. Desmoplastic melanomaĭesmoplastic melanoma was described as a variant of spindle cell melanoma in 1971. Others tumours it can be confused with are described below. Spindle cell melanoma can be easily confused with other spindle cell tumours. What is the differential diagnosis for spindle cell melanoma? Cytokeratin stains are negative in spindle cell melanoma.In spindle cell melanoma, a higher proportion of cells show Ki-67, cyclin D1, and survivin after staining.The markers S100, SOX10, p75, HMB-45, laminin T, laminin NT, Melan-A, and c-KIT are positive after staining in spindle cell melanoma.Special stains may be used to differentiate spindle cell melanoma from other spindle cell tumours. A pagetoid spread of atypical melanocytes in spindle cell melanoma, associated with lentigo maligna.Greater cellular cohesion is seen on cytology than with epithelioid types of melanoma.A high mitotic index (the ratio of cells undergoing mitosis over the total amount of cells). Uniform, wavy, and slender nuclei, with variable size and shapes ( pleomorphism) and variable nuclear atypia (abnormal appearance of cell nuclei).An abundance of spindle-shaped tumour cells (> 90% of a tumour).įeatures of spindle cell melanoma under microscopy include: Ī combination of histological clues and immunohistochemistry markers are required to diagnose spindle cell melanoma. The diagnosis is generally made on a biopsy of the lesion, but it can also be commonly mistaken for another tumour histologically. Its non-specific features may lead to delays in the diagnosis of spindle cell melanoma, which is often not suspected clinically.
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