BH10 Granulomatous scarring alopecia associated with rheumatoid arthritis: a case report with distinct folliculocentric granulomas histologically mimicking granulomatous alopecia areata
Authors: Kubba Faris , Allery Peter , Alfallooji Yasmin , Veriatch Ophelia , Martyn-Simmons Claire 
Published: June 2023

Abstract
A 54-year-old woman presented with an 8-month history of a superficial erythematous skin lesion on the lower quadrant of her left breast and scarring hair loss in the vertex confirmed by diffuse central alopecia with erythema and tufted hairs. She also reported an 8-year history of seropositive rheumatoid arthritis and a history of breast cancer that was treated by surgery, followed by radiotherapy and tamoxifen. On histological examination, punch biopsy of the scalp showed a distinct folliculocentric pattern of multi­nucleated giant cells associated with a dense lymphocytic infiltrate in the hair follicular isthmic and infundibular areas extending into the subcutis, with some hair follicular tufting. Immunohistochemistry confirmed the T-cell nature of the lymphocytes. Punch biopsy of the breast showed noncaseating granulomas in the upper and lower dermis. This folliculocentric pattern was well demarcated and not associated with a granulomatous reaction to other skin adnexa. The interfollicular areas were relatively spared. There were no significant lymphocyte epidermotropism, Pautrier microabscesses or atypical lymphocytes. The differential diagnosis of the scalp included granulomatous folliculotropic mycosis fungoides; however, in our case, there was association with longstanding rheumatoid arthritis. Other differential diagnoses included granulomatous drug reaction and chronic infections such as mycobacteria and fungi. A very similar folliculocentric pattern has been described in only a handful of extremely rare cases of granulomatous alopecia areata (Wilk M, Zelger BG, Zelger B. Granulomatous alopecia areata. J Cutan Pathol 2014; 41:329–31); however, the granulomas are mainly in the hair bulb and spare the higher section of the hair follicle. The lesion in the breast was an area of previous radiotherapy for breast cancer. Other working diagnoses of the breast lesion included interstitial granulomatous dermatitis and palisading and neutrophilic dermatitis. Treatment consisted of potent topical and systemic steroids, immunosuppression, phototherapy and tumour necrosis factor-α inhibitors. Spontaneous resolution, periods of flares and remission, and treatment-resistant forms have been described. We have reported a case of scarring alopecia with a distinct pattern of folliculocentric noncaseating granulomas associated with granulomatous dermatitis in the breast as a cutaneous manifestation of rheumatoid arthritis. This hair loss is a result of an autoimmune-mediated reaction to the skin and hair follicles. Although folliculocentric noncaseating granulomas have been described in the hair bulb in very rare case reports of granulomatous alopecia areata, this pattern of folliculocentric isthmic and infundibular granulomas has not been clearly described before and needs to be better studied. Early diagnosis by skin biopsy is needed to start treatment in order to avoid permanent scarring hair loss.