To the Editor:
We read with interest the article by Tsai et al (March 2002) (1) but several points make us doubtful about the diagnosis of primary pulmonary choriocarcinoma, as follows:
1. There is no comment concerning the technique (physical examination? ultrasonography? CT scan? MRI? other?) adopted to exclude for certain that the patient had no testicular lesion. Moreover, it is well known that the "burnt-out" phenomenon occurs in germinal tumors in general, and in choriocarcinoma in particular. Choriocarcinoma is likely to metastasize greatly prior to detection of the primary lesion, leaving only zones of scarring and hemosiderin-laden macrophages in the testis. (2)
2. Chest radiographs and CT scanning displayed bilateral pulmonary involvement by ground-glass opacities and nodules, showing many clinicoradiologic similarities with the previously report by McGowan et al, (3) who described a testicular choriocarcinoma with pulmonary metastases presenting as ARDS. These authors correctly underlined that only at autoptic examination, "the right testicle was essentially replaced by choriocarcinoma but was the same size as the uninvolved left one."
3. We have investigated two solitary pulmonary nodules in adult men (one of whom presented with gynecomastia) showing a dimorphic neoplasms characterized by polygonal mononuclear cells closely admixed with multinucleated syncytiotrophoblast-like cells in a hemorrhagic and necrotic background, thus sharing many morphologic features with a choriocarcinoma. Both tumors displayed a nuclear immunoreactivity for thyroid transcription factor (TTF)-1, the best immunohistochemical marker of pulmonary origin. Although a weak cytoplasmic immunostaining for [beta]-human chorionic gonadotrophin was noted, such tumors have been classified as pleomorphic carcinomas with choriocarcinoma-like features in accordance to the 1999 World Health Organization classification of lung tumors, (4) but not as primary choriocarcinomas of the lung. Besides, cyto- and syncytiotrophoblast cells are completely negative for TTF-1.
4. Finally, it is well documented that many nontrophoblastic malignancies may produce and/or express ectopic placental hormones, including primary conventional lung carcinomas. (5) Granted the diagnosis of pulmonary choriocarcinoma is debatable and far from being clarified, (6) the authors recommended the use of a urine pregnancy test as a rapid diagnostic method of primary pulmonary choriocarcinoma. We retain that a more detailed and rigorous clinicopathologic analysis should be preferred before one can establish such a diagnosis.
Correspondence to: Giulio Rossi, MD, Department of Morphologic Sciences, Section of Pathology, University of Modena and Reggio Emilia, Policlinico, Via del Pozzo, 71-41100 Modena, Italy; e-mail: email@example.com
(1) Tsai J-R, Chong I-W, Hung J-Y, et al. Use of urine pregnancy test for rapid diagnosis of primary pulmonary choriocarcinoma in a man. Chest 2002; 121:996-998
(2) Burr ME, Javadpour N. Germ-cell tumors in patients with apparently normal testes. Cancer 1981; 47:1911-1915
(3) McGowan MP, Pratter MR, Nash G. Primary testicular choriocarcinoma with pulmonary metastases presenting as ARDS. Chest 1990; 97:1258-1259
(4) Brambilla E, Travis WD, Colby TV, et al. The new World Health Organization classification of lung tumours. Eur Respir J 2001; 18:1059-1068
(5) Marcillac I, Troalen F, Ghillani P, et al. Free human chorionic gonadotropin [beta] subunit in gonadal and nongonadal neoplasms. Cancer Res 1992; 52:3901-3907
(6) Ikura Y, Inoue T, Tsukuda H, et al. Primary choriocarcinoma and human chorionic gonadotrophin-producing giant cell carcinoma of the lung: are they independent entities? Histopathology 2000; 36:17-25
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