CASE REPORT
A 68-year-old Japanese man with a reddish plaque on the forehead for several years and alopecia on the scalp for 9 months was referred to our department. A physical examination revealed alopecic reddish plaques measuring 3 cm in diameter on the forehead and scalp (Figure 1a). Lymph nodes were not swollen around the head or neck. A dermoscopic examination of the reddish plaque on the forehead showed multiple round brownish yellow dots with a whitish rim in the follicular ostium and red dots in the interfollicular area (Figure 1b). A peripheral blood examination revealed no increases in the level of the soluble interleukin 2 receptor or the number of atypical lymphocytes. A histopathological examination with hematoxylin & eosin staining showed i) an eosinophilic substance in the dilated infundibulum and a pale basophilic substance in the isthmus and outer root sheath (Figure 1c), ii) focal follicular spongiosis and vacuolar alterations at the interface between the outer root sheath and the dermis, iii) the follicular and perifollicular infiltration of lymphocytes without atypia, and iv) dilated capillary vessels in the upper dermis. The substance deposited in the hair follicle was stained with Alcian blue at pH 2.5 (Figure 1d). Based on the findings obtained, the patient was diagnosed with idiopathic follicular mucinosis and the relevant alopecia. The patient was treated 4 times each month with triamcinolone acetonide injections, with resulted in the attenuation of lesions after 4 months (Figure 1e).