Custom Search
|
|
Dermpath-India Pathology of Neurothekeoma |
Cellular Neurothekeoma - Pathology Infographics
|
Neurothekeoma is a rare, benign, dermal tumour. Site, age, sex: It is mainly located on the face, neck, arms and shoulders of young adults, and is more frequent in females. This lesion should also be suspected in older patients. Predisposing factors: Local trauma and estrogen use have been identified as triggering factors. This may explain the 2:1 ratio in females. Clinical presentation: It is as an asymptomatic, pink-erythematous, dome-shaped, solitary papule, with a slow growth rate. Microscopic images: Visit: Nerve Sheath Myxoma; Multilobular tumour composed of nests and fascicles of spindle or epithelioid cells with vesicular nuclei. Only focal myxoid change is evident. Rarely the tumour may demonstrate infiltrative growth pattern, brisk mitotic activity and cytological pleomorphism. These atypical features do not influence the prognosis of the tumour. Depending on the amount of myxoid matrix, Neurothekeoma can be classified into cellular Neurothekeoma (< 10% myxoid matrix), mixed Neurothekeoma (10 - 50% myxoid matrix) and myxoid Neurothekeoma (> 50% myxoid matrix). Immunohistochemistry: Neurothekeoma is almost always positive to melanoma specific antigen (NK1/C-3) and CD10. PGP9.5 is positive if antigen retrieval method is used. The tumour is S-100 protein, HMB-45, Melan-A and CD56 negative. It is sometimes positive to smooth muscle actin and neuron specific enolase. The cell of origin for Neurothekeoma is still unknown. Nerve sheath myxoma has been often linked to myxoid Neurothekeoma. It has been argued that Neurothekeoma has nerve sheath differentiation and is part of Nerve sheath myxoma. Although this remains controversial due to the lack of positive reaction to S-100 protein in all Neurothekeoma variants. The tumour probably has a fibrohistiocytic origin. Atypical Neurothekeoma: An atypical variant of Neurothekeoma (Atypical Neurothekeoma) has recently been described. Features: - Larger tumours (upto 6 cm) of deep penetration (skeletal muscle and subcutaneous fat involvement), - Diffuse infiltrative borders, - Vascular invasion, - A high mitotic index (>3 mitosis per 10 high power fields) and - Pleomorphism. This variant has been incompletely characterized and its clinical behavior is not entirely understood because of the scarcity of reports. In a series involving 10 Atypical Neurothekeoma patients, no local recurrence or metastasis was found in 1 to 5 years of follow-up. It seems that this "histologic aggressiveness" is not correlated with a "clinical aggressiveness". Still, it is preferable to perform a complete excision of ANT with free margins, until they are more accurately characterized. Ref: Atypical or worrisome features in cellular neurothekeoma: a study of 10 cases. Atypical neurothekeoma: a new case and review of the literature. Atypical cellular neurothekeoma. Atypical cellular neurothekeoma a diagnosis to be aware of. Differential diagnosis: Neurofibroma, Schwannoma or neuroma variants ; Fibrohistiocytic tumour and Nerve sheath myxoma. Spindle cell lesion with atypia and mitotic activity from head and neck area in an elderly individual, which stains positively with S100 protein, is more likely to be Desmoplastic Melanoma. One should carefully check dermo-epidermal junction. However a junctional component is not always present in Desmoplastic Melanoma. Ref: Cellular neurothekeoma: case report and its (un) relation with nerve sheath myxoma Anais Brasileiros de Dermatologia. 2015;90 (3 Suppl 1):156-159. doi:10.1590/abd1806-4841.20153402 Visit: Nerve Sheath Myxoma;
|
|
|
