Extrauterine Epithelioid Trophoblastic Tumor of Lung in a 35-year-old Woman
A 35-year-old multiparous woman was transferred to Asan Medical Center because of abnormal findings on lung imaging. She was admitted to the regional tertiary hospital because of abdominal pain, nausea, and vomiting 10 days prior to presentation to Asan Medical Center. During a work-up for evaluating the cause of her abdominal pain, a 2.7-cm pulmonary nodule was incidentally discovered in an abdominal computed tomography (CT) scan. Subsequently, a chest CT scan revealed that the nodule was located in the basal segment of the left lower lobe. The nodule had a well-defined lobule, whereas no other definite nodules or active lesions were found in the lungs (). For further evaluation, the patient was referred to Asan Medical Center. At the time of admission, the patient's vital signs were stable and her physical examination was unremarkable. The results of all laboratory tests were within normal limits.\nA lung needle biopsy was performed, the results of which indicated a few atypical cells that were positive for p63 and cytokeratin in a necrotic background. We believed that the characteristics of the nodule indicated squamous cell carcinoma. In 18-fluorodeoxyglucose positron emission tomography, the nodule showed a maximum standardized uptake value of 1.6 in the basal segment of the left lower lobe that indicated low metabolic activity. No other significant hypermetabolic lesions were found.\nThe follow-up chest CT performed after 1 month indicated that the mass had enlarged to 3.3×3.0 cm. No definite evidence of lymphadenopathy was seen in the hilar mediastinum. Because distant metastasis was not evident in brain magnetic resonance imaging or a bone scan, we performed video-assisted left lower lobectomy in addition to mediastinal lymph node dissection.\nOn gross examination, an ill-defined firm mass measuring 3.2×2.5×2 cm was observed. The mass was yellowish gray, firm, and granular with necrosis and an anthracotic pigment at the cut surface. Microscopic examination indicated that the mass was well-circumscribed and had replaced the normal pulmonary parenchyma. The tumor cells had a relatively uniform, mononuclear epithelioid appearance and were arranged in nests or cords. They had eosinophilic cytoplasm and irregular nuclei with prominent nucleoli. Hyaline-like materials were observed surrounding the tumor nest. Mitoses were occasionally observed (). Tumor cells had positive immunoreactivity for p63 (), beta-human chorionic gonadotropin (β-hCG) (), cytokeratin, inhibin (), sal-like protein 4, and placental alkaline phosphatase. Immunohistochemical staining for human placental lactogen, alpha-fetoprotein, and CD30 was negative.\nWe consulted the department of gynecology for pelvic examination ultrasonography, the findings of which were unremarkable. Endometrial curettage revealed normal menstrual-phase endometrium. The results of the postoperative serial serum β-hCG and carbohydrate antigen 19-9 tests were within normal limits at that time.\nOn postoperative day 3, the patient was discharged without complications. She received conservative treatment after that and underwent regular follow-ups in the outpatient clinic. After 15 months, a follow-up chest CT did not show any evidence of recurrence.