Clinicopathological features, therapeutic options, and significance of CD103 expression in 15 patients with follicular mucinosis

BACKGROUND: Follicular mucinosis (FM) is generally divided into a primary benign idiopathic form and a secondary form associated with mycosis fungoides. OBJECTIVE: To analyze the clinical and pathological features of FM and explore the pathological significance of CD103 expression. METHODS: In this case series, we retrospective analysis the clinical, pathological, treatment and follow-up treatment of 15 cases of FM. The expression of CD103 in all cases was detected by immunohistochemistry. RESULT: A total of 15 patients were enrolled, 7 were primary follicular mucinosis (P-FM) and 8 were mycosis fungoides-associated follicular mucinosis (MF-FM). Lesions of both P-FM and MF-FM are difficult to distinguish, present with red or dark red plaques and follicular papules. Pathologically, MF-FM showed more significant infiltrates of folliculotropic lymphoid cells, and the amount and proportion of CD103+ cells were significantly higher than that in P-FM. Follow-up data were available for 13 patients. Three cases were resolved after surgical resection, two patients were marked improved after oral administration of hydroxychloroquine and three times ALA photodynamic therapy respectively. The rest patients showed only modest efficacy. CONCLUSION: FM should be differentiated based on pathological characteristics and treatment response, CD103 is helpful in differential diagnosis of FM.