Ann Thorac Surg 2005;80:e3-e4
© 2005 The Society of Thoracic Surgeons
Case report
Benign Oncocytoma of the Trachea
Maarten Van Genechten, BMa,*,
Katrien Schelfout, MDb,
Paul R.G.A. Germonpré, MD, PhDc,
Koen Deschepper, MDd,
Paul E.Y. Van Schil, MD, PhDa
a Department of Thoracic and Vascular Surgery, University Hospital of Antwerp, Edegem
b Department of Pathology, University Hospital of Antwerp, Edegem
c Department of Pulmonary Medicine, University Hospital of Antwerp, Edegem
d Department of Pulmonary Medicine, Maria Middelares Hospital, Sint-Niklaas, Belgium
Accepted for publication March 3, 2005.
* Address reprint requests to Dr Van Schil, Department of Thoracic and Vascular Surgery, University Hospital of Antwerp, Wilrijkstraat 10, Edegem, B-2650 Belgium (Email: paul.van.schil{at}uza.be).
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Abstract
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A 16-year-old girl was referred with a presumed muco-epidermoid carcinoma of the distal trachea, which was diagnosed by bronchoscopic biopsy. She underwent tracheal resection and end-to-end anastomosis. Final pathologic examination of the resected specimen revealed a benign oncocytic adenoma. This neoplasm is composed predominantly of oncocytes and is extremely rare in this location.
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Introduction
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Primary tracheal tumors in young patients rarely occur; two-thirds of them having a benign histology such as hemangioma and granular cell tumor. Most frequently encountered malignant tumors are muco-epidermoid carcinomas and histiocytomas. We report a case of a benign oncocytic adenoma of the trachea that should be differentiated from an oncocytic carcinoid and muco-epidermoid carcinoma. A 16-year-old girl was investigated because of acute hemoptysis without fever, cough, chills, or night sweats. A small tracheal tumor was present on a chest computed tomographic scan (Fig 1). Bronchoscopic biopsy showed a low-grade mucoepidermoid carcinoma, and the patient was referred to our department for surgical treatment. Through a right posterolateral thoracotomy, a lower tracheal resection was performed. Jet ventilation was started, and 3 cm of trachea was excised. Frozen section examination of the cranial and caudal section was negative. An end-to-end anastomosis was performed with a continuous polypropylene suture interrupted at three places. A plaster cast was applied to maintain flexion of the head for 5 days. Postoperative bronchoscopy at 8 days showed granulation tissue at the anastomosis, which was not obstructive. Hemophilus influenza was cultured from the sputum and treated accordingly. In the following weeks, abundant granulation tissue at the anastomotic site was partially removed by bronchoscopic excision, followed by insertion of a silicone stent. Follow-up at 15 months showed a stable condition without signs of recurrence.
Macroscopically, a solid protruding lesion of 0.5 x 0.9 cm was found. The lesion consisted of hard, nodular white tissue with a brown surface. Histologically, the tumor cells were arranged in trabeculae, rounded groups and sheets, separated by thin fibrovascular stroma. Rarely, glands were formed with periodic acid-Schiff-positive, diastase resistant and Alcian blue positive secretes in their lumina. The tumor cells or oncocytes had abundant eosinophilic granular cytoplasm, central round nuclei, and often distinct nucleoli (Fig 2). No mitoses were found. The mitochondria in the oncocytes could be highlighted by phosphotungstic acid hematoxylin stain as deep-blue cytoplasmic granules.
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Fig 2. Sheets of oncocytes are present with eosinophilic cytoplasm separated by thin fibrovascular stroma. (Hematoxylin and eosin staining; x200.)
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The tumor cells showed no immunoreactivity for S100 protein and the neuroendocrine markers chromogranin A, synaptophysin, Leu 7 and neuron specific enolase. No myoepithelial or basal cell participation was present. There were no mucinocytes, and also squamous cell differentiation was absent. The surrounding lymph nodes had normal histologic morphology.
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Comment
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Final pathologic examination of the resected specimen revealed a benign oncocytoma. An oncocytoma is a glandular or epithelial tumor composed of large cells with cytoplasm that is granular and eosinophilic due to the presence of abundant mitochondria [1].
The first description of an oncocytoma, defined as a neoplasm composed predominantly or entirely of oncocytes, was made in 1932 by Jaffè [2], who described an oncocytoma of the parotid gland. In the following years, oncocytomas were discovered in many other organs such as the kidney, salivary gland, lung, and thyroid [3]. A tracheal localization of an oncocytic adenoma has not been reported yet.
Malignant oncocytomas are rare, but they do exist. They demonstrate malignant histologic features or behavior with local recurrences and distant metastases that were absent in our case. They are mainly found in the salivary and thyroid gland and the nasal mucous membrane [4]. Nielsen [5] described a malignant bronchial oncocytoma. A distinction should be made between oncocytic adenoma, carcinoid, and muco-epidermoid carcinoma [5, 6]. Specific characteristics are listed in Table 1. In our case, mitochondrial hyperplasia was highlighted by phosphotungstic acid hematoxylin staining with the lack of neuroendocrine differentiation excluding an oncocytic carcinoid tumor. Therefore, definitive diagnosis was an oncocytic adenoma.
Primary tracheal tumors are rare. In the series of Grillo and colleagues [7], muco-epidermoid carcinomas and carcinoids together account for 8.6% of primary tracheal cancers. Mucoepidermoid tumors (ie, the tumor that was initially diagnosed in our case) account for 0.2% of lung carcinomas and 1% to 5% arise from either the bronchi or trachea of which there are two distinct groups (ie, low-grade and high-grade). Distinction is made by histology based on necrosis, mitotic activity, and nuclear polymorphism. Low-grade tumors occur in childhood and are usually benign. There may be desmoplasia or elastasis in response to the tumor. An oncocytic muco-epidermoid carcinoma was first reported in the trachea by López-Terrada [8]. In our case, final pathologic examination excluded a low-grade oncocytic muco-epidermoid carcinoma because the tumor lacked mucinocytes, squamous cell differentiation, and desmoplasia (Table 1).
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References
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- Weiss LM, Gaffey MJ, Warhol MJ, et al. Immunocytochemical characterization of a monoclonal antibody directed against mitochondria reactive in paraffin-embedded sections Mod Pathol 1999;4:596-601.
- Jaffè H. Adenolymphoma of parotid gland Am J Cancer 1932;16:1415.
- Chang A, Harawi SJ. Oncocytes, oncocytosis, and oncocytic tumors Pathol Annu 1992;27(Pt 1):263-304.
- Hamperl H. Benign and malignant oncocytoma Cancer 1962;15:1019.[Medline]
- Nielsen AL. Malignant bronchial oncocytomaa case report and review of the literature. Hum Pathol 1985;16:852-854.[Medline]
- Fechner RE, Bentinck BR. Ultrastructure of bronchial oncocytoma Cancer 1973;31:1451.[Medline]
- Grillo HC. Surgery of the trachea and bronchi. London: Hamilton; 2004. pp. 207-248.
- Lopez-Terrada D, Bloom MG, Cagle PT, Ostrowski ML. Oncocytic mucoepidermoid carcinoma of the trachea Arch Pathol Lab Med 1999;123:635-637.[Medline]
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Abstract
Introduction
