A report describes a case of a 30-year-old man who presented with the chief complaint of an asymptomatic progressively enlarged scalp mass with alopecia for 1 year. He denied any history of significant weight loss, malaise, fever, bone pain or dyspnea. 

He showed no other systemic symptoms, neither had any family history of similar lesions. 

Dermatological examination showed a 5-cm-diameter large, hard, smooth-surfaced, rubbery to firm, erythematous mass on the occipital scalp and decreased hair density in the area overlying the mass. The patient showed no other lesions on the remaining skin and mucosal surfaces. Other physical examinations were unremarkable.

Skin biopsy of the scalp lesion demonstrated nodular cell infiltration of large mononuclear cells with abundant eosinophilic cytoplasm and kidney-shaped nuclei admixed with lymphocytes, eosinophils, neutrophils and multinucleated giant cells, in the histopathology. Immunohistochemical analysis revealed infiltrated cells to stain positive for cluster of differentiation 1a (CD1a) and S100, whereas CD68 stained negative.

The clinical and histopathological examinations confirmed the diagnosis as Langerhans cell histiocytosis (LCH).

He underwent further examinations to evaluate the disease extent. Routine laboratory results showed normal values, including complete blood count and metabolic and hormonal panels. Bone marrow biopsy revealed normocellular marrow with multilineage maturation that was negative for LCH. Whole-body MRI revealed a normal pituitary gland. Chest and abdominal CT revealed multiple cystic lesions in both lungs, suggesting pulmonary LCH; however, he showed no abnormality in the abdominal area. These findings prompted the disease stage to be multisystem LCH (skin and pulmonary systems).

He received chemotherapy consisting of vinblastine, methotrexate and prednisolone. The patient showed gradual improvement in the skin lesions and thus received advice to continue the treatment. He also received a schedule for a follow-up chest CT to re-evaluate his pulmonary LCH.

Source: Pomsoong C, Suchonwanit P. A case of extensive mass on the scalp with alopecia. Skin Appendage Disord. 2022;8(1):73-7.