J Thorac Cardiovasc Surg 2005;130:1198-1199
© 2005 The American Association for Thoracic Surgery
Clear cell carcinoma of the lung revisited
Juan C. Garzon, MD
a
,
Fernand M. Lai, MD
b
,
Tony S.K. Mok, MD
c
,
Anthony V. Manlulu, MD
a
,
Calvin S.H. Ng, MD
a
,
Tak Wai Lee, MD
a
,
Anthony P.C. Yim, MD
a
,
*
a Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China.
b Department of Pathology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China.
c Department of Clinical Oncology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China.
Received for publication April 7, 2005; accepted for publication April 18, 2005.
* Address for reprints: Anthony P. C. Yim, MD, Professor of Surgery and Chief of Cardiothoracic Surgery, Department of Surgery, The Chinese University of Hong Kong, Hong Kong SAR, China. (Email: yimap{at}cuhk.edu.hk).
| |
Manlulu, Yim, Garzón (left to right)
|
|
Clear cell carcinoma (CCC) of the lung is uncommon, and thus far only 51 cases have been reported in the literature. Presentation as an endobronchial lesion is even more unusual.
1
We present this case to illustrate clinical and pathologic aspects of this rare lung cancer.
Clinical Summary
A 37-year-old male patient was seen with persistent cough and intermittent hemoptysis for 3 months. Chest radiography revealed right upper lobe atelectasis. Chest computed tomography demonstrated a 4.7-cm right hilar mass closely abutting the superior vena cava, encasing the right main bronchus, and protruding endoluminally into the right main bronchus (Figure 1). There was no evidence of either nodal or distant metastasis. The patient underwent rigid bronchoscopy, which confirmed a polypoid mass originating from the right upper lobe bronchus protruding into and causing complete obstruction of the right main bronchus. The endobronchial mass was cored out and confirmed to be CCC. The patient underwent a few days of aggressive chest physiotherapy and then underwent right upper lobe sleeve lobectomy.
View larger version (145K):
[in this window]
[in a new window]
|
Figure 1. Chest computed tomographic scan showing tumor encasing right upper lobe bronchus, attached to superior vena cava, and protruding through right main bronchus (arrow).
|
|
Grossly, the right upper bronchus was filled with a whitish, solid tumor 1.2 cm in diameter and 3.0 cm long, with slight extension to the right main stem bronchus. Histologically, the tumor was characterized by sheets of distinctive ovoid clear cells with ill-defined and infiltrative margins (Figure 2). The tumor had grown through the bronchus into the peribronchial cartilage and infiltrated many hilar nerves but spared the hilar lymph nodes. The bronchial epithelium adjacent to the tumor also exhibited clear cytoplasmic changes. The tumor cell ultrastructures showed primitive intercellular junctions, abundant cytoplasmic glycogen with few to many mitochondria, and a poorly developed endoplasmic reticulum. The tumor cells shared with the normal bronchial mucosa a similar immunoreactivity to cytokeratins CK7 and AE1/AE3 and to the transcriptional protein p63, whereas they were negative for the marker of renal cell carcinoma, the thyroid transcription factor-1 expressed by alveolar pneumocytes, and the neuroendocrine markers chromogranin and synaptophysin.
View larger version (174K):
[in this window]
[in a new window]
|
Figure 2. Photomicrograph of CCC showing infiltrative pattern, with clear cytoplasm and moderate pleomorphism (arrow). (Hematoxylin and eosin, x120.)
|
|
Discussion
As a pathologic entity this particular subtype may not constitute a distinct tumor from the other types of clear cell tumors, as suggested in the early 1980s.
2,4
However, further clinicopathologic, immunohistochemical, and ultrastructural studies of subsequent case reports support CCC as a distinct subtype of large cell carcinoma with purely clear cell features or classified into squamous or adenomatous variants, depending on the type of cellular differentiation.
3
In our case, no squamous or adenomatous differentiation was seen, and the tumor grew into and completely occluded the right main bronchus. This biologic behavior appears to be more benign than that seen in other types of non–small cell lung cancer.
Conclusion
CCC has rarely been reported in the literature, and cases of endobronchial compromise are even rarer. Histopathologically, this tumor must be differentiated from metastatic renal cell carcinoma, benign sugar tumor of the lung, predominant squamous mucoepidermoid carcinoma, and myoepithelial tumor. Immunohistochemical staining of tumor cells facilitates the differential diagnosis of these entities. Because of the low metastatic potential of these lesions and their rarity of recurrence, the role of chemotherapy for these lesions is dubious.
References
- Iyoda A, Hiroshima K, Toyozaki T, Tsukamoto Y, Haga Y, Fujisawa T, et al. Clear cell adenocarcinoma with endobronchial polypoid growth. Pathol Int 2000;50:979-983.[Medline]
- Gaffey MJ, Mills SE, Ritter JH. Clear cell tumors of the lower respiratory tract. Semin Diagn Pathol 1997;14:222-232.[Medline]
- Hsu AA, Yeo CT, Ang HK, Ng HS, Ong YY. Clear cell carcinoma of the lung—a case report. Ann Acad Med Singapore 1992;2:827-829.
- Edwards C, Carlile A. Clear cell carcinoma of the lung. J Clin Pathol 1985;38:880-885.[Abstract/Free Full Text]
