Sarcomatoid renal cell carcinoma. An immunohistochemical and ultrastructural study

Sarcomatoid renal cell carcinoma: case report and review of literature

Sarcomatoid renal cell carcinoma is a tumour with aggressive behaviour. It is a form of dedifferentiated carcinoma with high incidence of metastases to the lungs. We report a case of 55-year-old male who presented with complaints of loin pain and hematuria. The biopsy confirmed sarcomatoid variant of renal cell carcinoma.

Sarcomatoid renal cell carcinoma with scant epithelial components in an Angora cat

CASE HISTORY

A 6-year-old, neutered, female Angora cat presented with a history of lethargy and anorexia for 2 months and a clinically palpable and gradually enlarging, solid mass in the abdominal cavity extending from the last costal arch to the pelvic cavity.

CLINICAL FINDINGS

Examination of the cat revealed jaundice, dehydration and hypothermia. Haematological manifestations included lymphopenia and substantial decrease in haematocrit value. Biochemical analysis of the blood revealed hypoglycaemia, three-fold elevated blood urea nitrogen values, increased level of serum aspartate aminotransferase and increased total bilirubin while the creatinine level was normal. Ultrasonographic examination of the abdomen showed a disrupted and large hypoechoic area around the left kidney. The cat was anaesthetised and the left kidney was removed, but the cat died following surgery.

PATHOLOGICAL FINDINGS

On post-mortem examination, the left kidney was markedly enlarged and both the cortical and medullary parenchyma were replaced by confluent, multilobulated, pale tan-white, firm nodular masses protruding above the capsular surface. Metastasis was not observed. Cytological examination revealed a population of spindle-shaped cells of variable size, with abundant coarse chromatin and occasionally prominent nucleoli. Initial sections of the kidney were indicative of undifferentiated sarcoma confirmed by immunohistochemistry revealing vimentin-positive and cytokeratin-negative results in all tumour tissues. Additional sections showed very small amounts of both cytokeratin-positive and vimentin-positive areas.

DIAGNOSIS

Sarcomatoid renal cell carcinoma (SRCC) with scant epithelial components originating from left kidney.

CLINICAL RELEVANCE

Clinical and pathological features were similar to those of human SRCC, even though there was no evidence of metastases. Immunohistochemistry for vimentin and cytokeratin may be useful for definitive diagnosis of renal cell carcinoma with sarcomatoid differentiation, although staining of sections from several different parts of the tumour may be necessary. When a primary renal tumour is presented, SRCC should be considered as this diagnosis may influence treatment protocols and the clinical outcome.

A case of robot-assisted laparoscopic radical prostatectomy in primary small cell prostate cancer

Primary small cell carcinoma of the prostate is a rare and very aggressive disease with a poor prognosis, even in its localized form. We managed a case of primary small cell carcinoma of the prostate. The patient was treated with robot-assisted laparoscopic radical prostatectomy and adjuvant chemotherapy. Herein we report this first case of robot-assisted laparoscopic radical prostatectomy performed in a patient with primary small cell carcinoma of the prostate.

Prostate cancer with small-cell morphology: an immunophenotypic subdivision

OBJECTIVE

To study the immunophenotypic characteristics and clinical outcome of morphologically undifferentiated prostatic carcinoma with small-cell morphology (U-PC-SCM).

MATERIAL AND METHODS

Sixteen patients with U-PC-SCM were enrolled. The streptavidin-biotin complex immunohistochemical method was used on paraffin-embedded tissue sections to test positivity for prostate-specific antigen, prostate-specific acid phosphatase, CD57, androgen receptors, CK8-18, epithelial membrane antigen, carcinoembryonic antigen, CD56, neuron-specific enolase, chromogranin, synaptophysin, serotonin, various hormones, thyroid transcriptional factor-1 and Ki-67/MIB1.

RESULTS

Based on immunophenotypic criteria, we identified two groups of patients. The final diagnosis was U-PC (Gleason score 10) in Group 1 (n=9) and pure or mixed neuroendocrine small-cell carcinoma in Group 2 (n=7). Group 1 underwent total androgen blockade (TAB) with no major response and had a median survival of 9 months. In Group 2, three patients underwent TAB, two of whom died of progressive disease. The third patient showed a partial response (PR) for 18 months but eventually relapsed with liver metastatic lesions. He was then treated with cisplatin + etoposide and showed a PR for 3 months and survived for 5 months after the initiation of the second-line chemotherapy (CTH) treatment. The other four patients received six cycles of cisplatin + etoposide. There were two complete responses of >14 and >22 months, respectively and 2 PRs of 11 and 17 months, respectively, the partial responders surviving for 14 and 21 months, respectively.

CONCLUSION

U-PC-SCM with a neuroendocrine immunophenotype is a histogenetically distinct entity with different clinical and laboratory manifestations which responds well to a cisplatin + etoposide CTH regimen.

SARCOMATOID RENAL CELL CARCINOMA IN A BINTURONG (ARCTICTIS BINTURONG)

An adult, female binturong (Arctictis binturong) was examined due to lethargy, inappetence, and an abdominal mass. Diagnostic investigations, including radiographs, abdominal ultrasound, clinical laboratory findings, and a fine-needle aspirate of the mass, were suggestive of a sarcoma with metastasis. Necropsy and histopathologic findings confirmed a widely disseminated sarcomatoid variant of a renal cell carcinoma, likely originating in the left kidney, with metastasis to the right kidney, spleen, pancreas, liver, mesenteric lymph nodes, and lungs. This is the first report of this neoplasm in a binturong and only the second report in the veterinary literature. Sarcomatoid renal cell carcinoma is a rare histologic variant of renal cell carcinoma that is aggressive, commonly metastatic, and associated with a very poor prognosis in humans. Accurate antemortem diagnosis of this tumor may be complicated by its biphasic morphology, which may resemble carcinoma or sarcoma (or both), often necessitating the use of immunohistochemical techniques.

Renal epithelial neoplasms: the diagnostic implications of electron microscopic study in 55 cases

Several unsettled histogenetic, nosologic and diagnostic considerations for renal epithelial tumors may have ultrastructural ramifications. Yet, a comprehensive electron microscopic study of renal epithelial neoplasms, in light of the recent classification, is not available. The ultrastructural findings from fifty-five renal epithelial neoplasms [31 clear cell renal cell carcinomas (RCC), 11 papillary RCC, 5 chromophobe RCC, 3 sarcomatoid RCC and 5 oncocytomas] were correlated with their light microscopic appearance. Clear cell RCC showed long microvilli similar to the brush border of the normal proximal tubules, with abundant cytoplasmic lipid and glycogen. Papillary RCC showed variably sized microvilli, and small amounts of cytoplasmic lipid, but no glycogen. Chromophobe RCC showed many cytoplasmic vesicles and abnormal mitochondria, with rare short and stubby microvilli. Renal oncocytoma showed many mitochondria with a few vesicles in the apical portion of the cytoplasm and rare short and stubby microvilli. The eosinophilic cell variants of clear cell RCC, papillary RCC and chromophobe RCC showed ultrastructural features similar to those of their respective prototypes, except for an increased numbers of mitochondria in the cytoplasm. One sarcomatoid clear cell RCC showed skeletal muscle differentiation. Two types of cytoplasmic inclusions, i.e. hyaline globules and granules similar to those in the Paneth cells (PC-like granules) were identified only in clear cell RCC, which displayed distinctive ultrastructural features. The current EM study demonstrates distinctive ultrastructural features of renal epithelial neoplasms. The findings lend additional support to the current classification of the pertinent tumor types, facilitate the differential diagnoses, and provide insights into the possible histogenesis of renal epithelial neoplasms.

Sarcomatoid renal cell carcinoma: the chromophobe connection

Eleven cases of sarcomatoid renal cell carcinoma were studied to determine the relative frequency of various subtypes of renal cell carcinoma that may be associated with sarcomatoid transformation. The epithelial components in these tumors were subcategorized according to established histologic criteria into chromophobe carcinoma (n = 6 cases), clear cell carcinoma (n = 3), papillary carcinoma (n = 1), and indeterminate (n = 1). In nine cases, material was available for immunohistochemical and DNA ploidy studies. The sarcomatoid component in all cases showed positivity for epithelial membrane antigen cytokeratin, indicating an epithelial derivation of these cells. Staining for mesenchymal markers was mostly negative, except for vimentin, which reacted strongly in all cases. DNA ploidy studies using flow cytometry and cell image analysis provided very similar results. Five of five chromophobe sarcomatoid carcinomas showed hypodiploid cell lines in the epithelial areas, whereas the sarcomatoid components mostly showed aneuploid peaks. In the remaining cases, DNA ploidy pattern was more variable. These findings indicate that chromophobe carcinoma may be the most frequent epithelial component associated with sarcomatoid renal cell carcinoma.

Sarcomatoid carcinoma: an ultrastructural study with light microscopic and immunohistochemical correlation of 10 cases from various anatomic sites

The histogenesis of sarcomatoid carcinoma has been an intriguing topic for pathologists for many years, and considerable evidence has accumulated in the fields of tissue culture, electron microscopy, and immunohistochemistry to support the concept that the sarcomatous cells derive by way of "divergent differentiation" (metaplasia) from the carcinomatous elements. We have studied a group of 10 cases of these tumors from various organs, using detailed ultrastructural analysis as well as light microscopic and immunohistochemical correlation. We found that there is an ultrastructural spectrum of differentiation from epithelial to mesenchymal type features and that the malignant spindle cells may be purely epithelial (3 cases), purely mesenchymal (3 cases), or a mixture of both (4 cases). Furthermore, individual cells may show biphasia, having desmosomes and tonofibrils as well as well developed rough endoplasmic reticulum and filaments with dense bodies. Electron microscopic and immunohistochemical results do not always correlate, illustrating the prudence of using several keratin antibodies, including wide-spectrum ones, and of performing electron microscopic examination on these tumors.