Primary pulmonary histiocytosis X in two patients with Hodgkin's disease.

The lungs may be involved in patients with histiocytosis X as part of the generalised disease, but histiocytosis X confined to the lungs without extrapulmonary involvement is rare. This report describes two cases of primary pulmonary histiocytosis arising in patients with Hodgkin's disease. It is impossible to state with certainty whether the pulmonary histiocytosis arose as a response to the defects of cell-mediated immunity, or as a consequence of immunosuppression by radiation and chemotherapy. In 1953 Lichenstein proposed the generic designation "histiocytosis X" to encompass three major entities -eosinophilic granuloma, Letterer-Siwe disease, and Hand-Schuller-Christian disease.' The ultrastructural demonstration of unique cytoplasmic pentalaminar structures referred to as Langerhans' or Birbeck's granules is highly characteristic of eosinophilic granuloma, Hand-Schilller-Christian disease, and Letterer-Siwe disease.2 3 Histiocytosis X confined to the lungs, and this lesion's concurrence with Hodgkin's disease, seem to be exceptional, and we report two such cases with their characteristic histological appearance.