Spindle cell melanoma

What is it spindle cell melanoma?

Spindle cell melanoma is rare histological variant of melanoma, characterized by the presence of spindle melanocytes [1]. In microscopy, is often confused with other skin and Soft fabric spindle cell cancers morphologies.

Desmoplastic Melanoma is a variant of spindle cell melanoma where there are varying proportions of spindle cells and desmoplastic cells present in the histology.

Further studies are needed to clarify the clinical manifestations, risk factors, treatment and management. forecast spindle cell melanoma.

Who gets spindle cell melanoma?

The current one incidence of spindle cell melanoma is unknown. Studies have suggested that between 1% and 14% of melanomas They are of the spindle cell variant (including desmoplastic melanoma) [2,3].

Spindle cell melanomas occur most frequently in Caucasian men, affecting men and women in a ratio of 1.6:1–1.9:1 respectively. The average age at diagnosis is 50–80 years [1,4].

What causes spindle cell melanoma?

The exact cause of spindle cell melanoma is unknown. Spindle cell melanoma shares some common symptoms. mutations with conventional (epithelioid) melanoma.

• Approximately 30% of spindle cell melanomas contain BRAF mutations the V600E substitution mutation It is the most common.
• NRAS and TEAM Mutations are rarely seen [4].

An association between spindle cell melanoma (including desmoplastic melanoma) and lentigo Malignant growth has been observed in sun-exposed areas [5].

What are the clinical features of spindle cell melanoma?

Spindle cell melanoma often presents as nonspecific amelanotic (no-pigmented) nodule in the patient's trunk, head or neck [1,3].

It can also be presented first as extended melanoma metastasis.

What are the complications of spindle cell melanoma?

Metastasis is the main complication of spindle cell melanoma. Delays in diagnosis may occur due to its atypical presentation histologically [1–3].

How is spindle cell melanoma diagnosed?

Its non-specific features may lead to delays in the diagnosis of spindle cell melanoma, which is often not suspected clinically. Diagnosis is usually made in a biopsy of the injury, but it can also be commonly confused with another tumor histologically [6].

A combination of histological clues and immunohistochemistry Markers are required to diagnose spindle cell melanoma [3].

Features of spindle cell melanoma under microscopy include:

• An abundance of spindle-shaped tumor cells (>90% of a tumor)
• Uniform, wavy and thin. nuclei, with variable sizes and shapes (pleomorphism) and variable nuclear atypia (abnormal appearance of cell nuclei)
• A high mitotic index (the proportion of cells undergoing mitosis on the total number of cells)
• Higher cellular Cohesion is seen in cytology that with epithelioid types of melanoma [2,7]
• A pagetoid dissemination of atypical melanocytes in spindle cell melanoma, associated with lentigo maligna [8].

Special stains can be used to differentiate spindle cell melanoma from other spindle cell tumors.

• S100, SOX10, p75, HMB-45, laminin T, laminin NT, Melan-A and c-KIT markers are positive after staining in spindle cell melanoma [2,3].
• In spindle cell melanoma, a higher proportion of cells show Ki-67, cyclin D1 and survivin after staining. [9].
• Cytokeratin The spots are negative in spindle cell melanoma [10,11].

Which is the differential diagnosis for spindle cell melanoma?

Spindle cell melanoma can easily be confused with other spindle cell tumors. Other tumors with which it can be confused are described below.

Desmoplastic melanoma

Desmoplastic melanoma was described as a variant of spindle cell melanoma in 1971 [6]. Recent studies now suggest that desmoplastic melanoma and spindle cell melanoma represent two distinct types of melanoma, such as differences in staining, genetic mutations and clinical manifestations have been found [3].

• When spindle cells account for >90% of a tumor, a diagnosis of spindle cell melanoma is made.
• When >90% of a tumor is composed of desmoplastic cells, a diagnosis of desmoplastic melanoma is made.
• Melanomas with spindle cells and desmoplastic components at varying levels between 10% and 90% are called mixed variants. [2,3,12].
• Collagen IV, CD68, MDM2 and trichrome are positive after staining in desmoplastic melanoma [3].
• HMB-45, laminin T, laminin NT, Melan-A and c-KIT are negative in desmoplastic melanoma [2,3].

Rush nevus

Reed naevus (also called pigmented spindle cell naevus) is a melanocytic nevi with a largely spindle cell appearance under microscopy. The architecture is symmetrical with good side demarcation, epidermal hyperplasiaand uniform nests of cells [9].

Cutaneous clear cell sarcoma

the differentiation of cutaneous clear cell sarcoma from spindle cell melanoma is largely histological, as both can stain positively for the same indicators: S100, HMB-45 and Melan-A. Cutaneous clear cell sarcoma tends to show uniform patterns of spindle cells fascicles (bundles) under microscopy, which are present throughout a tumor and enclosed by fibrous septa. stroma tends to be hyalinized, scleroticand lattice [13].

Leiomyosarcoma

Leiomyosarcoma pathology may be indistinguishable morphologically of melanoma

• Smooth muscle actin (SMA) staining is positive in leiomyosarcoma.
• S100, p75 or HMB-45 markers are negative after staining. [10,14].

Atypical fibroxanthoma

S100, p75 and HMB-45 markers are negative after staining in atypical fibroxanthoma [10].

Fibrosarcoma

• Vimentin is positive in fibrosarcoma.
• S100 and HMB-45 markers are negative after staining. [5,14].

Peripheral nerve sheath tumors

• S100, CD34 and GAP43 markers are positive after staining in peripheral nerve sheath tumors.
• HMB-45 and Melan-A are negative in peripheral nerve sheath tumors [10,15].

Dermatofibrosarcoma protuberans

• CD34 is positive in dermatofibrosarcoma protuberans.
• p75 is variable.
• S100 is negative [5,16].

Spindle cell scaly cell carcinoma

• Cytokeratin stains such as 34betaE12 are positive in spindle cell squamous cell carcinoma.
• S100 and HMB-45 are usually negative after staining.
• p75 is variable [10,11].

What is the treatment for spindle cell melanoma?

Treatment for spindle cell melanoma is similar to that for other forms of melanoma. Surgical excision It is the first step in management [1].

What is the outcome for spindle cell melanoma?

Although the trend to nodal The incidence is low, most spindle cell melanomas present with advanced disease, with a worse prognosis in Caucasian men over 66 years of age. [3].

Advanced disease with lymph nodes and distal Metastasis is associated with worse outcomes in spindle cell melanoma, as are higher tumor grades, which have been associated with worse disease-specific and overall survival [1].