Intermammary Hidradenitis Suppurativa: A Case Report.

Hidradenitis suppurativa (HS) is a chronic relapsing inflammatory skin disease clinically characterized by recurrent, deep-seated, painful, subcutaneous nodules, sinus tracts, and hypertrophic scarring. This disease affects hair follicles in the apocrine gland-bearing areas such as the axillae, buttocks, as well as the genital and perineal areas. In women, the predilection sites of HS include the anterior part of the body, most commonly on the breasts, inframammary area, and groin. Intermammary location possibly represents a rare phenotype presentation. A case of intermammary HS in a 24-year-old woman was reported. The patient is overweight and is a smoker. Frequent friction and excessive sweating between big breasts were admitted. Chronic painful nodules accompanied by sinuses and scars between the breasts were found. Histopathological examination from a skin lesion on the intermammary area showed follicular occlusion, follicular hyperkeratosis, and destroyed hair follicles. There were also apocrine glands and hair follicles surrounded by massive neutrophils, lymphocytes, and histiocytes, suggestive of HS. The patient was given rifampicin and clindamycin. Clinical improvements were observed on the third week of observation. Typical lesion distribution is one of the criteria for establishing a definite diagnosis of HS. If the lesion is on an atypical site, it must be accompanied by at least one on the typical site. However, the predilection sites of HS often varied. The intermammary area is an intertriginous area, and mechanical friction, follicular occlusion, and rupture of the dilated follicles may contribute to the development of HS in the area. The existence of a typical lesion in an atypical distribution, without any lesion present in typical predilection sites, cannot rule out diagnostic consideration of HS. Therefore, clinicians should be aware and consider the diagnosis of HS even when the required criteria of HS are not fulfilled.