The existence of a lesion in bone which histologically appears granulomatous, non-specific, and is infiltrated with histiocytes and eosinophilic leukocytes was first reported, simultaneously, in 1940, by Otani and Ehrlich (13) and by Lichtenstein and Jaffe (10). Undoubtedly the lesion had been seen previously, but its exact nature and course were not described. Since 1940, a number of authors have reported single examples or small groups of cases, leading to considerable discussion of the relationship of this lesion to the older entities of Hand-Schüller-Christian's disease, or lipogranulomatosis, and Letterer-Siwe's disease, also called reticulosis or non-lipoid histiocytosis (Jaffe and Lichtenstein, 8; Green and Farber, 5; Mallory, 11). Disagreement concerning the exact terminology is, therefore, to be expected. “Solitary granuloma of bone” was proposed by Otani and Ehrlich (13). Green and Farber (5) suggested “‘destructive granuloma of bone,’ ‘single’ or ‘multiple’ as the case may be, adding parenthetically ‘Hand - Schüller - Christian syndrome.’” Eosinophilic granuloma, as used by Jaffe and Lichtenstein (8), seems preferable and will be used in this paper. It is our purpose to present the roentgen findings in 9 cases, confirmed by biopsy, which were seen in an Army General Hospital, together with the pertinent clinical and laboratory findings. In each case the biopsy sections were reviewed and the histopathologic diagnosis confirmed by the Army Medical Museum. Case I (Fig. 1): White male, 21 years of age. Onset September 1943 with constant headaches and pain in the orbits. There were no convulsions, vomiting, or visual changes. In October, a fluctuant, tender, but non-pulsating mass developed in the left forehead. A roentgenologic bone survey revealed a solitary lesion in the left frontal bone; no similar lesions were present in other bones. Laboratory Findings: The Kahn test was negative. Nothing unusual was found on urinalysis, which was negative for Bence-Jones protein. The white blood count was 5,700 (66 per cent polymorphonuclears, 5 per cent eosinophils); blood serum calcium 10 mg. per 100 c.c.; phosphorus 3.5 mg. per 100 c.c.; total protein 6.1 gm. per 100 c.c., basal metabolic rate + 7; blood cholesterol 194 mg. per 100 c.c. Although at biopsy in November the tumor appeared grossly malignant, involving both tables of the skull, the histologic picture was the classical one of eosinophilic granuloma. Case II (Fig. 2): White male, 24 years of age. Onset October 1943 with trembling and numbness of right hand. The patient had two episodes of unconsciousness but no headaches. A small mass was palpable in the left parietal region. Physical examination showed the right arm to be weaker than the left. Except for the left parietal lesion, a roentgenographic bone survey was negative. Laboratory Findings: The Kahn test was negative.