CASE REPORT Annals of Nuclear Medicine Vol. 2, No. 2, 89-93, 1988 Scintigraphic evaluation of two cases with alveolar soft part sarcoma Hitoya OHTA,*,** Masaki ISHI,* Keigo ENDO,** Junji KONISHI,** Yoshihiko KOTOURA,*** Takao YAMAMURO*** and Kanji TORIZUKA**** *Department of Internal Medicine, Kobe Tamatsu Hospital **Department of Nuclear Medicine, Kyoto University Hospital ***Department of Orthopedic Surgery, Kyoto University Hospital ****Fukui Medical School Two cases of alveolar soft part sarcoma were examined with gallium-67 citrate (67Ga), technetium-99m-methylenediphosphate (99mTc-MDP) and technetium-99m(V)-dimercaptosuccinic acid (Tc(V)-DMS) to compare the sensitivity of these three radiopharmaceuticals. All scintigrams were positive with primary tumor, and images with Tc(V)-DMS were the best. Skull metastasis could be also detected by all agents, but scintigrams with lung metastases were negative. In scintigraphic evaluation of alveolar soft part sarcoma, Tc(V)-DMS may be a better agent than 67Ga or 99mTc-MDP. Key words : Alveolar soft part sarcoma, 99mTc-MDP, 67Ga-citrate, 99mTc(V)-dimercaptosuccinic acid INTRODUCTION ALVEOLAR SOFT PART SARCOMA is an uncommon neoplasm. According to Enzinger and Weiss, the frequency is estimated as between 0.5 % and 1.0% of all soft tissue sarcomas,1 and only a few scintigraphic images of this type of tumor have been previously reported.2 The usefulness of gallium-67 citrate (67Ga), technetium-99m-methylenediphosphate (99mTc-MDP) and technethium-99m(V)-dimercaptosuccinic acid (Tc(V)-DMS) scintigraphies in soft tissue sarcomas has been reported.3-6 Recently we made a scintigraphic evaluation of 2 cases of alveolar soft part sarcoma. The images were demonstrated and the usefulness of Tc(V)-DMS was discussed. MATERIALS AND METHODS Commercially available 67Ga and 99mTc-MDP were used in the present study. Tc(V)-DMS was produced at the Daiichi Radioiso- Received April 6, 1987; revision accepted August 31, 1987. For reprints contact : Hitoya Ohta, M.D., Department of Nuclear Medicine, Kyoto University Hospital, 54, Shogoinkawara-cho, Sakyo-ku, Kyoto 606, JAPAN. tope Laboratories (Tokyo) as previously reported.6,7 In brief, vials containing 1.36 mg of dimercaptosuccinic acid, 1.26 mg of NaHCO3, 0.11 mg of SnCl2.2H2O, and 30 mg of glucose were lyophilized and stored at 4deg.C. Labeling was performed by the addition into the kit of 0.1 mg of 7% NaHCO3 with 23 ml of pertechnetate with the desired activity. Scintigrams were made 120 min, 120 min and 48 hrs after i.v. administration of 10 mCi 99mTc-MDP, 10 mCi Tc(V)-DMS and 2 mCi 67Ga, respectively, using a conventional gamma camera. These scintigraphies were performed within a period of 2 weeks. CASE REPORTS Case 1 A 26-year-old man noticed an asymptomatic diffuse swelling of the left thigh without precipitating cause, but underwent no therapy. One year later, he also noticed a tumor of 1 cm in diameter on his right forehead. The tumor increased in size rapidly. The forehead tumor was clearly demonstrated by Tc(V)-DMS and 67Ga, and intense uptake of 99mTc-MDP suggested bone reaction in the tumor margin (Fig. 1). Intense accumulation of Tc(V)-DMS in the left thigh was also recognized, but 67Ga and 99mTc-MDP accumulation were less intense (Fig. 2). Alveolar soft part sarcoma and its skull metastasis were confirmed at surgery (Fig. 3). Case 2 A 37-year-old man noticed a fist-sized tumor in his right thigh. He thought it was because of contusion and underwent no therapy. One month later, spasmodic coughing attacks occurred daily during the night or early in the morning. A chest film disclosed multiple coin-shaped lesions as shown in Fig. 4. Tc(V)-DMS. 99mTc-MDP and 67Ga localized in the tumor of the right thigh (Fig. 5). However, lung metastases were not detectable with any of the radiopharmaceuticals (Fig. 6). Tumor biopsy revealed alveolar soft part sarcoma. DISCUSSION Enzinger and Weiss describe that the ultimate prognosis of alveolar soft part sarcoma is poor despite the relatively slow growth of the tumor. The principal metastatic sites are the lung followed by the brain and skeleton.1 In the therapy of soft tissue tumors, it is important to diagnose the extent and localization. This paper describes scintigraphic imagings of alveolar soft part sarcoma using 67Ga, 99mTc-MDP and Tc(V)-DMS. Tc(V)-DMS images were better than 67Ga or 99mTc-MDP images for detecting the primary tumor. Skull metastasis was also detectable, but 99mTc-MDP showed bone reaction in the tumor margin. The metastatic tumor itself could be detected most clearly by Tc(V)-DMS. No agents could demonstrate a clear accumulation for lung metastases. There are many factors which influence the outcome of tumor imaging, such as tumor uptake ratio compared with the surrounding normal tissue, tumor area, tumor depth and photon attenuation. The failure to detect the lung metastases might be caused by these factors, even though the primary tumor and the lung metastases had the same absolute count rate per gram tissue. These results suggested that scintigraphic study might not be a satisfactory method to assess alveolar soft part sarcoma. However, scintigraphy is easy and noninvasive and can be repeated frequently. Tc(V)-DMS was thought to be the first choice of radiopharmaceuticals for scintigraphic examination of alveolar soft part sarcoma. ACKNOWLEDGMENTS The authors express their appreciation to Hiroshi Iwamoto, Katsuya Terao, Bungo Onoue, Takashi Nakamura and Shinji Akita for their valuable assistance. REFERENCES 1. Enzinger FM, Weiss SW: Soft Tissue Tumors, St Louis, CV Mosby, 1983, pp 780-787 2. Bartusch L, Meister P, Bull U, et al : Das alveolare Weichteilsarkom der Skelettmuskulstur. Munch Med Wschr 116: 923-928, 1974 3. Felix SC, Terry MH, William FB: Radionuclide imaging of soft tissue neoplasms. Semin Nucl Med 11: 266-276, 1981 4. Pinsky SM, Henkin RE: Gallium-67 tumor scanning. Semin Nucl Med 6: 397-408, 1976 5. Blatt CJ, Hayt DB, Desai M, et al : Soft tissue sarcoma: Imaged with Tc-99m pyrophosphate. NY State J Med 77 : 2118-2119, 1977 6. Ohta H, Endo K, Fujita T, et al: Imaging of soft tissue tumors with Tc(V)-99m dimercaptosuccinic acid, a new tumor-seeking agent. Clin Nucl Med 9 : 568-573, 1984 7. Yokoyama A, Hata N, Horiuchi K, et al : The design of a pentavalent Tc-99m-dimercaptosuccinic complex as a tumor imaging agent. Int J Nucl Med Biol 12: 273-279, 1985