Ann Thorac Surg 2007;83:310-312
© 2007 The Society of Thoracic Surgeons
Case Reports
Large Clear Cell Tumor of the Lung Mimicking Malignant Behavior
Alpha M. Kavunkal, MCha,*,
Murugu Sundara Pandiyan, MCha,
Madhu Andrew Philip, MCha,
Kancheepuram N. Parimelazhagan, MCha,
Marie T. Manipadam, MDb,
Vijit Koshy Cherian, MCha
a Department of Cardiothoracic Surgery, Christian Medical College & Hospital, Vellore, Tamil Nadu, India
b Department of Pathology, Christian Medical College & Hospital, Vellore, Tamil Nadu, India
Accepted for publication April 17, 2006.
* Address correspondence to Dr Kavunkal, Department of Cardiothoracic Surgery, Christian Medical College & Hospital, Vellore, Tamil Nadu 632 004, India (Email: alphakavi{at}hotmail.com).
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Abstract
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An 18-year-old man presented with a large (12 x 10 cm) cystic mass involving the lower lobe and lingula of the left lung on computed tomography. Intraoperatively a large cystic mass was seen densely adherent to the left lung and the chest wall. A left pneumonectomy was performed because of the dense adhesions and extreme vascularity. Pathologic examination revealed a benign sugar cell tumor of the lung. We believe this is the first case report of such a large, clear cell tumor of the lung, mimicking malignant behavior in terms of vascularity and local invasion and requiring pneumonectomy.
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Introduction
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The clear cell (sugar) tumor of the lung is a rare benign neoplasm originally described in 1963 by Liebow and Castleman [1]. However only sporadic cases of this neoplasm have been reported. It is a highly vascular tumor, composed of clear cells with large amounts of intracytoplasmic glycogen, hence called "sugar" tumor. An unusual clinical presentation of a large benign sugar cell tumor of the lung is being reported.
An 18-year-old man presented with progressive shortness of breath and left-sided chest pain for 1 year with recurrent episodes of hemoptysis for 1 month. He was treated for pulmonary tuberculosis 4 years ago and is a known smoker. Physical examination revealed decreased air entry over the left lower hemithorax. Chest roentgenogram showed a large homogenous, rounded opacity in the left hemithorax continous with the mediastinal shadow (Fig 1). Computed tomographic scan revealed a large (12 x 10 cm) cystic mass involving the left lower lobe and extending onto the lingula. Bronchoscopy showed extrinsic compression of the left lower lobe bronchus. Pulmonary function test was normal and sputum for acid fast bacilli were negative. An ultrasound-guided biopsy of the tumor revealed clear cell neoplasm. An ultrasound abdomen did not show any renal mass.
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Fig 1. Chest roentgenogram showing a large (12 x 10 cm) homogenous, rounded opacity in the left hemithorax.
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The patient underwent a left posterolateral thoracotomy through the fifth intercostal space. A large (12 x 10 x 8 cm) firm cystic mass was visualized, which was adherent to the lower lobe, part of the upper lobe of the left lung, and to the chest wall. The plane between the tumor and the lung was extremely vascular. An attempt to create a plane between the tumor and the lung, so as to enuculate it, resulted in diffuse bleeding. This diffuse hemorrhage was technically difficult to control and led to hemodynamic instability. Further attempts to achieve a plane of separation to conserve the left upper lobe were futile, as the vascularity of the tumor and its adherence to the rest of the lung was dense. Hence a left pneumonectomy was performed.
On gross examination the tumor appeared grey white, soft, and necrotic with foci of hemorrhage. The rest of the lung was unremarkable. Microscopic examination showed sheets with little internal clustering of polygonal cells with clear to granular pale, eosinophilic cytoplasm with oval nuclei separated by thin fibrovascular septae. There were no mitotic figures. There were foci of hyalinization. The tumor cells were immunoreactive for human melanoma black (HMB-45) and S-100, and were nonreactive for cytokeratin 7 characterizing the benign clear cell tumor (Fig 2) [2]. The tumor cells were negative for epithelial markers, cytokeratins, and epithelial membrane antigen, thus ruling out a clear cell carcinoma of the lung, either primary or secondary. Although there are recent reports describing CD 117 positivity in clear cell sugar tumors, this case was negative for CD 117 [3].
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Fig 2. Immunostaining for human melanoma black (HMB–45) (x200). Tumor cells showing cytoplasmic positivity for HMB–45.
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The patient had an uneventful postoperative recovery and was discharged on postoperative day 7. He continues to do well 1 year after pneumonectomy with no evidence of metastasis.
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Comment
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Patients with benign sugar cell tumor usually ranged in age from 40 to 60 years with equal sex prevelance. These lung tumors are usually incidentally detected on routine chest roentgenograms or computed tomographic scan. Grossly benign clear cell tumor predominantly appears as a well circumscribed, peripheral nodule measuring 3 cm or less in diameter. Microscopy shows glycogen granules in the cytoplasm of these clear cells and immunohistochemical staining is unique, being positive for HMB–45 and S–100 and negative for cytokeratin-7. Pulmonary sugar tumor now regarded as a member of the conceptual group of tumors called myomelanocytomas is viewed as a purely epithelioid myomelanocytoma [3].
Our patient was unique because he presented with hemoptysis. There have been only two such reports [4, 5]. The other unique feature of this tumor was that it was extremely large, involving the lower lobe and part of the upper lobe requiring pneumonectomy. There has been no report to date in the English literature of such a giant tumor with benign clear cell pathology. Traditionally, clear cell tumors have been considered benign. However, a patient who died with clear cell tumor metastatic to the liver was reported in 1988 [6]. Gaffey and colleagues [7] also reported another patient who had hepatic metastasis 10 years after diagnosis. From their study of eight cases, they suggested that clear cell tumor of the lung greater than 2.5 cm in diameter that exhibit necrosis or symptomatology should be considered as potentially metastasizing neoplasms. Therefore the benign behavior is probably variable, and the aspects that indicate this behavior need to be clarified.
In summary, the unusual presentation of a benign, clear cell tumor as a large tumor of the lung mimicking malignant behavior in terms of tumor vascularity and local invasion is rare. The need for pneumonectomy for large benign lung tumors is again unusual. The benign behavior is variable, therefore complete surgical resection is probably the best chance to improve survival and quality of life.
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References
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- Liebow AA, Castleman B. Benign clear cell tumors of the lung Am J Pathol 1963;43:13.[Medline]
- Gaffey MJ, Mills SE, Zarbo RJ, Weiss LM, Gown AM. Clear cell tumor of the lungImmnunohistochemical and ultrastructural evidence of melanogenesis. Am J Surg Pathol 1991;15:644-653.[Medline]
- Wick MR, Mills SE. Benign and borderline tumors of the lung and pleuraIn: Leslie KO, Wick MR, editors. Practical pulmonary pathology a diagnositc approach, 1st ed. Philadelphia: Churchill Livingstone; 2005. pp. 713-715.
- Kung M, Landa JF, Lubin J. Benign clear cell tumor (sugar tumor) of the trachea Cancer 1984;54:517-519.[Medline]
- Alfredo NCS, Flavia SN, Nelson H, Teresa YT. A rare cause of hemoptysis: benign sugar (clear) cell tumor of the lung Eur J Cardiothorac Surg 2004;25:652-654.[Abstract/Free Full Text]
- Sale GE, Kulander BG. "Benign" clear cell tumor (sugar tumor) of the lung with hepatic metastasis ten years afer resection of pulmonary primary tumor Arch Pathol Lab Med 1988;112:1177-1178.[Medline]
- Gaffey MJ, Mills SE, Askin FB, et al. Clear cell tumor of the lung: a clinicopathologic, immunohistochemical and ultrastructural study of eight cases Am J Surg Pathol 1990;14:248-259.[Medline]
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Abstract
Introduction
