Ann Thorac Surg 2002;74:579-582
© 2002 The Society of Thoracic Surgeons
Case report
Thymic basaloid carcinoma with hepatic metastasis
Toshihiro Matsuo, MD*a,
Ryozo Hayashida, MDa,
Keita Kobayashi, MDa,
Yoshihisa Tanaka, MDa,
Shoji Ohtsuka, MDa
a Departments of General Thoracic Surgery and Surgery, Shin-Koga Hospital, Kurume, Japan
Accepted for publication February 18, 2002.
* Address reprint requests to Dr Matsuo, Shin-Koga Hospital, 120 Tenjin-cho, Kurume, Fukuoka 830-8577, Japan
e-mail: kenchan{at}toq.ne.jp
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Abstract
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A thymic basaloid carcinoma is rare, as is an unusual case with extra-thoracic metastasis. We report on a 41-year-old woman who had a thymic basaloid carcinoma with liver metastases. The patient underwent resection of the thymic basaloid carcinoma followed by curative partial hepatectomy. At 1 year later, another metastatic lesion developed in the residual liver, which was also curatively resected. The postoperative course was uneventful, and the patient is surviving without recurrence for 12 months, to date.
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Introduction
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A thymic basaloid carcinoma is reported to be a low-grade malignancy. However, its clinical features are unclear, because a basaloid carcinoma in the thymus is extremely rare. To date, only 8 cases have been reported. In all of these 8 cases, there was no extra-thoracic metastasis. Here we report an unusual case of thymic basaloid carcinoma with liver metastases.
A 41-year-old woman was admitted to our hospital presenting chest pain. On admission, all the laboratory data were within the normal ranges. A chest roentgenogram showed an abnormal shadow in the mediastinum, and also suggested right pleural effusion. A computed tomographic scan confirmed a heterogeneous mass in the anterior-mediastinum, with pleural effusion in the right thoracic cavity (Fig 1A).
Both an abdominal ultrasonograph and a computed tomographic scan also showed a small heterogeneous mass in the posterior segment of the liver (Fig 1B), suggesting a metastatic liver tumor. No other metastatic lesion was seen. Although a percutaneous needle biopsy of the mediastinal tumor was performed, a pathological diagnosis was inconclusive. Moreover, no malignancy was detected in the pleural effusion. Clinically, the diagnosis was a malignant tumor with hepatic metastasis. In a two-stage operation, the mediastinal tumor was initially resected with partial resection of the right lung, through a median sternotomy. The resected mediastinal tumor measured 5.0 x 3.0 x 2.5 cm and was surrounded by a fibrous capsule (Fig 2A). The tumor was solid with hemorrhage and cyst formation. Microscopically, the tumor was composed of spindle to polygonal cells with scant cytoplasm and with mitotic figures (Fig 2B). Immunohistochemically, the tumor cells were negative for neuron-specific enolase, and chromogranin. The histological diagnosis was thymic basaloid carcinoma. At 3 weeks after the resection of the thymic carcinoma, a posterior segmentectomy of the liver was performed. The resected specimen of the liver tumor was also surrounded by a fibrous capsule and was solid with hemorrhage and cyst formation, resembling the basaloid carcinoma in the thymus (Fig 2C). Microscopically, features similar to those of the basaloid carcinoma were seen, and vascular invasion was noted. The postoperative course was good. However, at 12 months after the partial hepatectomy, another metastatic lesion was detected in the residual liver. Hepatic metastasis was suspected again, and a second curative resection was performed. The subsequent postoperative course has been uneventful. This patient has survived without recurrence for 12 months, to date, after the repeated hepatectomy.
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Fig 1. (A) Computed tomographic scan of the chest shows an anterior mediastinal mass with cystic lesions. Right pleural effusion also is seen in the right thoracic cavity. (B) Computed tomographic scan of the abdomen shows a cystic lesion with solid area in the posterior segment of the liver.
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Fig 2. (A) The thymic tumor was well circumscribed, and was multiloculated. There was a centrally located solid nodule. (B) The nodule showed alveolar structure. There was prominent palisading of the tumor cells around the neoplastic islands and nests. Tumor cells were basaloid in appearance (hematoxylin and eosin; original magnification, x 50). (C) The gross appearance of resected liver showed a multiloculated cyst with a solid mass.
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Comment
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A thymic carcinoma is a relatively rare neoplasm. In 1978, Levine and Rosai classified thymic carcinoma into five groups: squamous cell, lymphoepithelioma-like, clear cell, sarcomatoid, and undifferentiated [1]. In 1982, Snover and colleagues described three additional types of thymic carcinoma: mixed small cell undifferentiated squamous cell, mucoepidermoid, and basaloid [2]. Among these, thymic basaloid carcinoma is extremely rare, and only 8 cases, to date, have been reported in the English literature (Table 1). Suster and Rosai reported that thymic basaloid carcinoma showed low-grade histology [3]. However, among the 9 cases (including our case), distant metastasis has occurred in 3 (30%), involving pulmonary metastasis in 2, and liver metastasis only in the present case. It is therefore clear that thymic basaloid carcinoma can show hematogenous metastasis. Surgical resection has been performed in all cases. However, the clinical benefit of resection, and of any adjuvant therapy (chemotherapy or radiotherapy) remains unclear. Of the 2 other cases having distant metastasis, 1 received adjuvant chemotherapy after the operation. Further follow-up is required to determine the efficacy of treatments and the long-term prognosis in these patients, and accumulation of cases is needed. The outcomes in previous cases appear to confirm that thymic basaloid carcinoma shows relatively low-grade histology, and, to date, there has been no death related to this carcinoma. In view of the long survival that can be expected with this low-grade malignancy, we believe that the resection of any distant metastasis from the thymic basaloid carcinoma is therefore warranted.
In summary, we have reported a rare case of thymic basaloid carcinoma with liver metastasis. This is an unusual case with extra-thoracic metastasis. Furthermore, extra-thoracic metastases were resected, and the prognosis has been good.
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Acknowledgments
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The authors thank Shinzo Takamori, MD, of the Kurume University School of Medicine for his advice.
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References
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- Levine G.D., Rosai J. Thymic hyperplasia and neoplasia: a review of current concepts. Hum Pathol 1982;6:613-630.
- Snover D.C., Levine G.D., Rosai J. Thymic carcinoma: five distinctive histological variants. Am J Surg Pathol 1982;6:451-470.[Medline]
- Suster S., Rosai J. Multilocular thymic cyst: an acquired reactive process-study of 18 cases. Am J Surg Pathol 1991;15:388-398.[Medline]
- Hofmann W., Moller P., Manke H.G., et al. Thymoma: a clinicopathologic study of 98 cases with special reference to three unusual cases. Pathol Res Pract 1985;179:337-353.[Medline]
- Iezzoni J.C., Nass L.B. Thymic basaloid carcinoma: a case report and review of the literature. Mod Pathol 1996;9:21-25.[Medline]
- Kawashima O., Kamiyoshihara M., Sakata S., et al. Basaloid carcinoma of the thymus. Ann Thorac Surg 1999;68:1863-1865.[Abstract/Free Full Text]
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Abstract
Introduction
