Unusual form of recurrent giant cell granuloma of the mandible and lower extremities in a patient with neurofibromatosis type 1.

We report on a girl with familial neurofibromatosis type 1 (Nf1) who at age 11 had multiple osteolytic lesions of the right mandible and the distal femoral and proximal tibial metaphyses bilaterally. No other skeletal component was affected, and no abnormalities were present on skeletal radiographs of her parents. Histologic examination of the mandibular and right femoral lesions revealed a "multinucleated giant cell process." Results of repeated routine laboratory and bone metabolic studies were within normal limits. The lack of reliable histologic criteria and the diagnostic problems in distinguishing among central giant cell granulomata, giant cell tumors of the jaw, cherubism, brown tumors resulting from (occult) hyperparathyroidism, Jaffe-Campanacci syndrome, McCune-Albright syndrome, Noonan-like/multiple giant cell lesion syndrome, and multiple nonossifying fibromas of bone are discussed.