CASE REPORT
A 70-year-old male presented with mild throat and chest discomfort for
four months. A chest x-ray was performed which demonstrated a left upper
lobe opacity. On further imaging, contrast-enhanced computed tomography
(CECT) chest demonstrated a heterogeneously enhancing oval soft tissue
density lesion (3x3x2.9 cm) with a lobulated outline and slight
speculation at places involving the apicoposterior segment of the upper
lobe of the left lung. Bronchoscopy demonstrated normal findings. He had
a history of renal cell carcinoma for which he underwent a right
nephrectomy 16 years ago, vertebral fusion surgery 24 years ago, and
cholecystectomy 17 years ago. He did not have a history of smoking. The
patient was then re-evaluated at our center with a CECT chest and
abdomen which showed a 3x3x3.2 cm lesion in the left upper lobe of the
lung without enlarged mediastinal lymph nodes. There was no visible
recurrence in the right kidney bed. (Figure-1)
CT-guided tru-cut biopsy from the upper lobe of the left lung lesion was
diagnosed as clear cell tumor favoring clear cell carcinoma. Later after
a month, wedge resection of the left upper lobe of lung was done
(Figure-2). Grossly, circumscribed tumor of maximum dimension of 3.5 cm
was noted (Figure 3). Histologic sections showed tumor cells arranged in
solid sheets and nests. These tumor cells were pleomorphic, polygonal in
shape with delineated cell membrane, central nuclei with vesicular
chromatin and abundant clear to eosinophilic cytoplasm. Some of the
cells showed prominent eosinophilic nucleoli (Figure 4A and 4B).
Immunohistochemistry was done to further confirm the diagnosis. On,
immunohistochemistry, tumor cells were positive for cytokeratin (CK
AE1/AE3), paired box gene (PAX8) , cluster of differentiation 10 (CD10),
vimentin, and weakly focal positive PAX2 and negative for CK7, CK20,
thyroid transcription factor 1 (TTF1) and P40 (Figure 5). The
histomorphological features along with immunohistcohemical analysis
favored the diagnosis of metastatic clear cell renal cell carcinoma.
The postoperative period was uneventful. The patient was stable without
any new symptoms at seven months of follow-up.