Follicular mucinosis: a review

Abstract

Follicular mucinosis (FM) is an epithelial reaction pattern characterized by follicular mucin accumulation. It has been described in association with various inflammatory and neoplastic cutaneous disorders. FM is generally divided into a primary benign idiopathic form and a secondary form usually occurring in association with cutaneous lymphomas (especially mycosis fungoides), among other entities. Distinction between the two forms can be challenging as they share many overlapping features and the lack of a single diagnostic tool to differentiate between the two. Making the distinction may require evaluating and correlating the clinical, histologic, immunohistochemical, and molecular studies together. Long‐term clinical follow‐up also remains very important. In this review, we describe the different entities associated with FM, its pathogenesis, and possible therapeutic options.

A case of nevoid follicular mucinosis in a child

“…6 FM usually presents as erythematous plaques, sometimes with follicular prominence and localized alopecia. 7 The Blaschkoid appearance of this lesion did not align with the traditional clinical features of FM. However, the new entity termed nevoid follicular mucinosis encompasses such cases of nevoid skin lesions distributed along Blaschko's lines with FM on histopathology.…”

“…FM is usually classified as either primary idiopathic, a benign form, or secondary FM, which can occur together with various other conditions including cutaneous lymphoma, hematologic malignancy, inflammatory disorders, and infections. 7 The majority of FM cases are associated with lymphoma, most commonly cutaneous T-cell lymphoma. 7 In particular, folliculotropic mycosis fungoides may present with FM as well as an atypical lymphocytic infiltrate of hair follicles, and it often occurs in the head and neck area.…”

“…7 The majority of FM cases are associated with lymphoma, most commonly cutaneous T-cell lymphoma. 7 In particular, folliculotropic mycosis fungoides may present with FM as well as an atypical lymphocytic infiltrate of hair follicles, and it often occurs in the head and neck area. 8 Before making a diagnosis of nevoid FM in this patient, it was therefore important to investigate the possibility of mycosis fungoidesassociated FM.…”

A single plaque on the chin

“…10 Despite being a benign condition, monitoring patients with FM for cutaneous T lymphoma is advised, especially in persistent cases, although the progression toward MF has not been observed in some studies. 1 There is no specific treatment for primary FM and treatment mo-…”

Metabolic and Nutritional Disorders Relevant in Dermatology

“…Differentiation between these two types is difficult due to their overlapping features. Primary cases commonly affect children and young adults (Khalil et al 2020). • Clinical feature: Primary cases are characterized by hypopigmented eczematous plaques and follicular papules (Fig.…”