A 41-year-old male presented at his local eye clinic with the primary complaint of decreased visual acuity (VA) in his left eye. Upon examination, a subretinal tumor mass was observed in his left eye, and he was subsequently referred to the Department of Ophthalmology, Osaka Medical College, Takatsuki, Osaka, Japan for more detailed examination and treatment. His medical and family history was unremarkable. His VA was RV = (1.2 × S-7.5D) and LV = (0.04 × S-8.0D), and his intraocular pressure was 17 mm Hg in both eyes. No abnormalities were noted in the right eye, but a few inflammatory cells were observed in the vitreous and anterior chamber of the left eye. Fundus examination showed no particular abnormalities in the right eye, but a large white protruding lesion of 10 papilla diameter (PD) (lateral diameter) ×8 PD (longitudinal diameter) in the macular region, and slightly temporal to it, in the left eye. B-scan ultrasonography (UD-8000; Tomey® Corp., Nagoya, Japan) was performed and revealed that the lesion in the left eye appeared to have high internal reflectivity. Examination by optical coherence tomography (OCT) (SPECTRALIS®; Heidelberg Engineering GmbH, Heidelberg, Germany) revealed no abnormalities in the right eye. In the left eye, a protruding lesion was observed with a homogenous shadow on the choroid and under the retina, which was complicated by exudative retinal detachment around it. Fluorescein angiography (TRC-50DX Type IA; Topcon Corp., Tokyo, Japan) showed slight fluorescein leakage in the peripheral region of the right eye. In the left eye, punctate fluorescein leakage corresponding to the tumor-like mass was noted at the early phase, and tissue staining and fluorescein pooling were observed from the middle to late phase. Indocyanine green angiography (TRC-50DX Type IA) revealed low fluorescence and filling delay in the area corresponding to the tumor mass. Whole-body contrast-enhanced computed tomography (CT) was performed, since the choroidal tumor was also suspected on the basis of the above findings. The CT results showed that there were enlarged lymph nodes throughout the body, including both sides of the neck, the supraclavicular fossa, both sides of the mediastinum, and the pulmonary hilum. Thus, the patient was subsequently referred to the Department of Respiratory Medicine at Osaka Medical College Hospital, and since sarcoidosis was suspected, a biopsy of the right cervical lymph nodes was performed at the Department of Plastic Surgery. The results showed a noncaseating epithelioid cell granuloma. Blood test results were as follows: the angiotensin-converting enzyme finding was 15.2 U/L (reference range 8.3–21.4 U/L), the soluble interleukin-2 receptor finding was 987 U/mL (reference range 145–519 U/mL), the toxoplasma IgM and IgG test findings were within the normal reference range, and the enzyme-linked immune absorbent spot assay finding (tuberculosis) was negative. Choroidal granuloma due to sarcoidosis was diagnosed on the basis of both the pathological examination results and the ophthalmologic findings. Steroid pulse therapy (methylprednisolone 1,000 mg for 3 days) was performed due to a rather large lesion compared with that of past reports. After one cycle of steroid pulse therapy, the prednisolone was tapered to 60 mg/day. Triamcinolone was once injected into the sub-Tenon capsule, but it was withdrawn due to an increase in intraocular pressure. After the initiation of steroid therapy, the choroidal granuloma gradually decreased in size, and the patient's VA gradually improved at 3 weeks and beyond after the start of treatment. At 2 months after the start of treatment, the choroidal granuloma was markedly decreased, the exudative retinal detachment had disappeared, and the patient's corrected VA had improved to 0.7. At 1 year after the start of treatment, the choroidal granuloma had further decreased, although atrophy of the retinal pigment epithelium was detected, and the patient's corrected VA was maintained at 0.8. There was no increase in intraocular pressure during the 1-year period of steroid pulse therapy.