Rapidly progressing mycosis fungoides presenting as follicular mucinosis

Abstract

Follicular mucinosis can occur as a primary idiopathic disorder or can arise in association with benign or malignant disease, most notably mycosis fungoides. We describe a patient with an aggressive folliculotropic variant of mycosis fungoides that initially presented as follicular mucinosis with alopecia. One month after the diagnosis of follicular mucinosis, a diagnosis of mycosis fungoides was made, and 3 months later inguinal lymph node involvement with mycosis fungoides developed. A skin biopsy specimen demonstrated prominent follicular mucinosis with folliculotropism of atypical cells and intrafollicular Pautrier's microabscesses. As demonstrated in this case, follicular mucinosis can be a presenting sign of rapidly progressive mycosis fungoides. In our review of follicular mucinosis and its association with mycosis fungoides, we found that the folliculotropic variant of mycosis fungoides appears more commonly to have an aggressive course than classic mycosis fungoides. (J Am Acad Dermatol 2000;43:635-40.).

Follicular mucinosis was first described by Pinkus1 and Braun-Falco2 in 1957. They used the term alopecia mucinosis to refer to a disease process of follicular degeneration leading to alopecia. This process is characterized histologically by mucin in the epithelium of the follicular outer root sheath and the sebaceous gland and is clinically characterized by sharply defined plaques or coalescing patches of follicular papules. Because alopecia is not always present, the condition was renamed follicular mucinosis by Jablonska, Chorzelski, and Lancucki3 in 1959. Follicular mucinosis may occur as a benign primary “idiopathic” disorder, or it may arise secondary to various benign or malignant diseases. 4,5 The primary form has two clinical courses. One occurs most commonly in children and young adults and is characterized by spontaneous regression after 2 months to 2 years. The other pattern occurs in slightly older adults and is chronic and relapsing. Secondary follicular mucinosis may be associated with a lymphoproliferative disorder, most commonly the cutaneous T-cell lymphoma mycosis fungoides (MF). The reported incidence of MF occurring in the setting of follicular mucinosis varies among studies, with an average association of 15%.6 MF may precede, occur simultaneously with, or develop up to decades after the diagnosis of follicular mucinosis. We report a case of a 44-year-old man who presented with follicular mucinosis and in whom histologically diagnostic MF developed 1 month later, with subsequent progression to inguinal lymph node involvement 3 months later. To our knowledge, this is the first reported case of follicular mucinosis associated with such an aggressive form of MF and emphasizes the importance of careful clinical and histologic surveillance of patients with follicular mucinosis.