RESUMEN
A familial lymphoproliferative disorder presented in three male siblings with primary pulmonary involvement manifested as either lymphoid interstitial pneumonia or an angiodestructive polymorphous infiltrate morphologically resembling lymphomatoid granulomatosis. The polymorphous infiltrate consisted chiefly of mature T-cells with a few B-cells and plasma cells, and gene rearrangement studies failed to show clonality. Epstein-Barr virus, frequently associated with proliferative lesions in males in the X-linked lymphoproliferative syndrome, was not demonstrated in any of the pulmonary lesions. An HLA haplotype shared among the affected siblings was A1, B8, DR4. The unusual clinical presentation plus the lack of involvement by EBV in the pulmonary lesions suggests that this is a previously undescribed familial lymphoproliferative disorder.