Cutaneous Manifestations of Castleman Disease: Histopathological Characteristics and Review of Literature.

Castleman disease (CD) is a poorly understood lymphoproliferative disorder characterized by enlarged lymph nodes. The spectrum of differential diagnoses is wide, and it is hard to differentiate from other diseases. Cutaneous involvement of CD is rare, and studies that describe cutaneous dermatopathology of CD are scarce. The aim of this study was to collect case reports of CD with cutaneous manifestations and identify potential relevant histopathological features. We found that cases of CD with cutaneous manifestations often exhibited dermal lymphoid follicles with follicle center infiltration of lymphocytes and plasma cells. These dermal follicles also had regressive or atrophic germinal centers and were penetrated by hyalinized vessels. Patients with CD also consistently exhibited perivascular and deep dermal inflammatory infiltrate, primarily composed of lymphocytes and plasma cells. We intend to raise awareness of this rare entity and provide more histopathological information regarding its dermatological manifestations.