精巣原発が示唆された精巣微小石灰化病変を有する後腹膜胚細胞腫瘍の2例 : 後腹膜胚細胞腫瘍の原発についての考察

Abstract

症例1:19歳男.腹痛と腹部腫瘤を主訴とし, 腹部CT上左後腹膜腔に10cm大の腫瘍, 肝, 肺に多発性の腫瘍を認め, 生検でYolk sac tumorであった.進行性胚細胞腫瘍と診断し, VIP変法を4コース施行し, 残存した病変に後腹膜リンパ節郭清術を施行した.その後, AFPの再上昇と脳転移を生じ頭部放射線照射, 脳動注, BEP療法を中心に全身化学療法を行った.その後左精巣に小石灰化像を認め, 左高位精巣摘出術を行った.10年後に後縦隔リンパ節腫大があり, 腫瘍摘出し, 病理学的には高分化型腺癌であった.症例2:57歳男.検診で胸部X線異常陰影を指摘され, 頸部リンパ節腫大, 肺, 後腹膜腫瘍があり, 原発性性腺外胚細胞腫瘍としてBEP療法が施行された.VIP療法と変法を併せて3コース追加したが後腹膜に残存病変を認め, 後腹膜リンパ節郭清術を施行した.超音波検査上右精巣は結節状の小石灰化像, 左精巣に砂粒状の微小な高エコー像を認め, 両側高位精巣摘出術を行った.2例とも精巣原発が示唆された

Two cases of germ cell neoplasm retrospectively considered to have been of testicular origin are reported. Case 1. A 19-year-old male with brain, liver and retroperitoneal tumors was diagnosed with yolk sac tumor by retroperitoneal tumor biopsy. After multidisciplinary treatment, a region of calcification was detected in the left testis on scrotal sonography and left high inguinal orchiectomy was performed. Case 2. A 57-year-old male with neck, lung and retroperitoneal tumors was diagnosed with yolk sac tumor by supraclavicular biopsy. From initial examination, scrotal sonography revealed a small calcified lesion in the right testis. After chemotherapy, high inguinal orchiectomy and retroperitoneal lymphadenectomy were simultaneously performed. Pathologic evaluation of these testicular specimens revealed calcification and a fibrous scar in correspondence with the clinical diagnosis. These changes were considered as scars of the primary testicular tumor due to burned-out tumor or the result of reaction to chemotherapy. Since a primary tumor of testicular origin may exist in the extragonadal germ cell tumor, it is important to examine the intrascrotal contents in detail in the case of so-called extragonadal germ cell tumors with palpably normal testes. In such cases, there are two possible conditions, an occult testicular tumor and a burned-out testicular tumor. We briefly reviewed 42 such cases in the Japanese literature. It appears that there are very few true extragonadal germ cell tumors, and that the possibility of primary testicular origin metastasizing from viable occult testicular tumor or burned-out testicular tumor with spontaneous regression is high in retroperitoneal germ cell tumors.