A Case Report and Brief Review of Facial Solitary Reticulohistiocytoma.

Reticulohistiocytoma is a localized form of reticulohistiocytosis without systemic involvement. This is a histiocytic reactive lesion which can arise on the skin or mucosa. A 60-year-old female presented with an ill-defined solitary reddish brown, firm, nontender nodule of size 1.5 × 1.5 cm, lateral to right nasolabial fold for 1 year. Histopathological examination showed irregular acanthosis in the epidermis and the dermis revealed collection of histiocytes in clusters, some of which showed eosinophilic cytoplasm which was suggestive of a benign histiocytic lesion. Immunohistochemistry showed scattered cell positivity for CD68 and S100. A final diagnosis of solitary adult onset reticulohistiocytoma was made and an elliptical excision was done. There is a need for clinicopathological correlation along with immunohistochemistry to diagnose this entity and differentiate from other mimickers. Reported cases of facial reticulohistiocytoma, of which two were reported from India, have been reviewed for a better understanding of this entity. [ABSTRACT FROM AUTHOR]