The cutaneous manifestations of atypical complete DiGeorge syndrome: a histopathologic and immunohistochemical study.

DiGeorge syndrome is a congenital anomaly with a constellation of findings that includes thymic hypoplasia. Only a small subset of patients with DiGeorge syndrome has complete athymia, classified as complete DiGeorge anomaly; one third of these patients show an eczematous dermatitis, oligoclonal T-cells and lymphadenopathy, known as atypical complete DiGeorge anomaly. Six biopsies from six patients with the distinctive clinical phenotype of atypical complete DiGeorge anomaly were studied. Every biopsy showed exocytosis (100%), parakeratosis, often confluent and spongiosis (100%). Neutrophilic abscesses (50%), dyskeratosis (67%) and satellite cell necrosis (50%) were seen. Perieccrine and perivascular inflammation were seen in half of the cases. Eosinophils were identified (83%); most commonly in both the epidermis and dermis. All of lymphocytes were CD3 positive. Most (83%) of cases contained T-cell intracellular antigen 1 (TIA-1) positive cells. Special testing of the selected patients using spectratyping identified oligoclonal T-cell populations. The presence of dyskeratotic keratinocytes, satellite cell necrosis and parakeratotic scale with neutrophils characterizes the cutaneous rash seen in this subset of complete DiGeorge syndrome patients. Such skin lesions from patients with DiGeorge anomaly should alert the pathologist to the potential diagnosis of atypical complete DiGeorge anomaly. The pathophysiologic role of the oligoclonal T-cells in this entity requires additional study.