Usefulness of ¹⁸F-Fluorodeoxyglucose-position emission tomography with computed tomography and gallium-67 scintigraphy for detection of Kaposi sarcoma lesions in a 40-year-old Japanese man with AIDS

Abstract

A 40-year-old Japanese man with acquired immunodeficiency syndrome was diagnosed with Kaposi sarcoma (KS) on the basis of the results of skin lesion biopsies. In addition, 18F-fluorodeoxyglucose-position emission tomography–computed tomography revealed abnormal fluorodeoxyglucose uptake in KS lesions, whereas gallium-67 scintigraphy did not show uptake of gallium. These findings indicate that combining these imaging modalities can help distinguish KS from other malignancies and opportunistic infections.

A 40-year-old Japanese man with acquired immunodeficiency syndrome presented with a several-month history of progressive bilateral leg pain and edema. He had had sex with other men and had been human immunodeficiency virus (HIV)-positive for at least 10 years but had never received any antiretroviral therapy (ART). Physical findings showed pale conjunctiva, generally enlarged lymph nodes, and decreased breath sounds in his right lung, and more notably in his left lung. There were multiple vascular papules and nodules with dark pigmentation and edema in both legs (Fig. 1). Laboratory examination demonstrated CD4 expression in 170 cells/μL and an HIV-1 RNA viral load of 68,000 copies/mL. The patient was diagnosed with Kaposi sarcoma (KS) on the basis of the pathology results of body skin lesions, right femoral skin lesions, and submental lymph node biopsies. As determined by immunostaining, the lesions were positive for herpes virus 8 (HHV-8), which causes KS, and the peripheral blood HHV-8 titer was elevated (6.5 × 10³ copies/10⁶ mL). The patient received ART and pegylated liposomal doxorubicin at fixed intervals. Whole-body ¹⁸F-Fluorodeoxyglucose-position emission tomography with computed tomography (FDG-PET/CT) revealed abnormal uptake in multiple cutaneous, cervical, intra-abdominal, and especially femoral lesions, whereas gallium-67 scintigraphy did not (Fig. 2, Fig. 3).

Fig. 1.

Macroscopic observations. Stiff edema and multiple vascular papules and nodules with pigmentation extending from the femur to the lower extremities are observed.

Fig. 2.

¹⁸F-Fluorodeoxyglucose-position emission tomography–computed tomography findings. ¹⁸F-Fluorodeoxyglucose-position emission tomography–computed tomography revealed multiple cutaneous lesions in both the femurs and the lower extremities.

Fig. 3.

Gallium-67 scintigraphy findings. Gallium-67 scintigraphy showed no abnormal accumulation of gallium.

FDG-PET/CT is a widely available technique based on increased glucose utilization by malignant cells and is useful for detecting malignancies including KS [1], even if the patients do not have HIV associated KS [2]. FDG-PET/CT was also useful in KS without any cutaneous lesions [3]. However, it does not distinguish KS lesions from other types of malignancies. In gallium-67 scintigraphy, KS lesions do not incorporate ⁶⁷Ga, although other malignant lesions do [4]. Therefore, in addition to biopsies, the combination of FDG-PET/CT and gallium-67 scintigraphy can be useful for detecting and staging KS.

Conflict of interest

The authors state that they have no conflicts of interest. Informed consent was obtained.