Clear cell papillary renal cell carcinoma and clear cell renal cell carcinoma arising in acquired cystic disease of the kidney: an immunohistochemical and genetic study.

Clear cell papillary renal cell carcinoma (RCC) is a recently established disease entity. However, there are few reports on genetic study of this entity. We report such a case with focus on genetic study. A 57-year-old Japanese man was found to have 3 renal tumors. Histologically, two tumors showed findings of clear cell RCC; and the other tumor showed findings of clear cell papillary RCC that was characterized by papillary growth pattern of neoplastic cells in cystic space with purely clear cell cytology. Immunohistochemically, tumor cells of clear cell papillary RCC were diffusely positive for PAX2 and cytokeratin 7, but negative for CD10, RCC Ma, and AMACR. In fluorescence in situ hybridization study for one clear cell papillary RCC, we detected polysomy for chromosome 7 and monosomy for chromosomes 17, 16, and 20. In addition, we detected mutation of VHL gene in clear cell RCC, but found no VHL gene mutation in clear cell papillary RCC. Finally, our results provide further evidence that clear cell papillary RCC may be both morphologically and genetically distinct entity from clear cell RCC and papillary RCC.

Immunohistochemical application of D2-40 as basal cell marker in evaluating atypical small acinar proliferation of initial routine prostatic needle biopsy materials.

D2-40 has been recently discovered as a lymphatic endothelial cell marker, and some investigators have found that D2-40 is also expressed in myoepithelial cells of salivary gland or breast. In this study, we evaluated D2-40 expression of basal cells and applied D2-40 immunohistochemistry in the combination of P504S, cytokeratin 5, and p63 for ten lesions with atypical small acinar proliferation (ASAP) in initial prostatic needle biopsy. As a result, D2-40 was expressed in basal cells, lymphatic endothelial cells, and some stromal fibroblasts of normal prostatic tissue. Among ten ASAP lesions, the final diagnosis of seven lesions was resolved by combination immunohistochemistry. D2-40 was comparable to cytokeratin 5 and p63 as a basal cell marker, and there were no lesions that failed to provide an accurate final diagnosis using only D2-40 immunohistochemistry without cytokeratin 5 or p63. However, we found some D2-40-positive stromal fibroblasts or D2-40-positive lumen-collapsed lymphatic vessels neighboring atypical glands. Pathologists should pay attention to avoid recognizing these cells as basal cells. In conclusion, the combination of immunohistochemistry of P504S, cytokeratin 5, p63, and D2-40 may contribute to the accurate diagnosis of ASAP in the initial prostatic needle biopsy.

Chromosomal abnormalities of clear cell renal cell carcinoma: frequent gain of chromosome 7.

Gain of chromosome 7 is well known to be a characteristic abnormality of papillary renal cell carcinoma (RCC). The purpose of the present study was to perform cytogenetic analysis of G-band karyotype in 16 clear cell RCC obtained from nephrectomy. The age of patients ranged from 50 to 79 years and the tumor size in largest dimension ranged from 1.8 to 6.2 cm. As a result, the structural abnormality of chromosome 3 was most frequently observed (eight clones). Loss of chromosome 3 and gain of chromosome 7 followed (four clones). Among four clones showing gain of chromosome 7, two were associated with the abnormality of chromosome 3 and the remaining two were devoid of the abnormalities of chromosome 3. In addition, none of all four tumors showing gain of chromosome 7 demonstrated any foci of papillary growth pattern. The present study shows that gain of chromosome 7 is not exclusive to papillary RCC, but it can be found in clear cell RCC as well, and this finding may represent a diagnostic pitfall in distinguishing clear cell RCC from papillary RCC.

Acquired cystic disease-associated renal cell carcinoma with gain of chromosomes 3, 7, and 16, gain of chromosome X, and loss of chromosome Y.

Acquired cystic disease (ACD)-associated renal cell carcinoma (RCC) has been recently described. To date, there are no reports on genetic findings of G-band karyotype of ACD-associated RCC. In this article, we report the first report of G-band karyotype of ACD-associated RCC. A 66-year-old Japanese man was found to have a left renal tumor during the follow-up of hemodialysis consequent to chronic renal failure. Left nephrectomy was performed. Histological examination of three tumors in the left kidney showed the cribriform or microcystic growth pattern of neoplastic cells with eosinophilic cytoplasm, and many oxalate crystals were observed. The G-band karyotype of ACD-associated RCC showed 49, X, +X, -Y, +3, +7, +16. These chromosomal abnormalities resemble those of sporadic papillary RCC that has been previously reported. Finally, we suggest that this tumor may show a close relationship between ACD-associated RCC and papillary RCC, but a large-scale study will be needed to clarify the relationship between ACD-associated RCC and papillary RCC.

Ureteral small cell carcinoma.

Ureteral small cell carcinoma is very rare; only eight cases have been reported in the literature. In this article, we report the ninth case of ureteral small cell carcinoma. A 79-year-old Japanese man presented with asymptomatic macrohematuria, and left nephroureterectomy was performed. The nonpapillary and broad-based tumor, which measured 3.7 x 3.7 x 2.0 cm, was seen in the lower portion of the left ureter just above the ureteral orifice. Microscopically, the tumor was composed of urothelial carcinoma and small cell carcinoma. Immunohistochemically, neoplastic cells of small cell carcinoma were focally positive for chromogranin A. In the normal ureteral mucosa adjacent to the tumor, some endocrine cells positive for chromogranin A and synaptophysin were identified. In conclusion, we suggest that endocrine cells in the ureteral urothelial epithelium may be precursor cells of ureteral small cell carcinoma.

Carcinoid tumor of the renal pelvis: consideration on the histogenesis.

Carcinoid tumor of the renal pelvis is an extremely rare neoplasm and only two cases have been previously reported in the English-language literature. Reported herein is a third case of carcinoid tumor arising in the renal pelvis. The tumor extending from the left renal pelvis into the left kidney was incidentally found in a 55-year-old Japanese woman. Macroscopically, the tumor was predominantly located in the dilated renal pelvis and was grayish-white on cut surface. Microscopically, neoplastic cells proliferated with a ribbon-like, trabecular, tubular and solid pattern. Furthermore, the tumor focally invaded the kidney parenchyma. No precursor lesion of neuroendocrine tumor was observed in the peripheral urothelial epithelium. Neither urothelial carcinoma nor teratoma component was observed within the tumorous mass. The cytoplasm of neoplastic cells was focally positive for Grimelius stain and focally positive for chromogranin A and synaptophysin. However, no neoplastic cells reacted with cytokeratins 7 and 20. Ultrastructurally, neoplastic cells contained dense core granules in the cytoplasm. Urologists and pathologists should recognize that carcinoid tumor may arise from the renal pelvis.

Mixed testicular germ cell tumor in an adult with cryptorchidism and Down's syndrome.

We here present a case of mixed testicular germ cell tumor in an adult with cryptorchidism and Down's syndrome. A 20-year-old Japanese man with a mass in the left inguinal region underwent orchidectomy as a left testicular tumor was suspected. Histology showed a mixed germ-cell tumor with embryonal carcinoma and yolk sac tumor with syncytiotrophoblastic giant cells occurring in a cryptorchid testis. Chromosomal analysis of peripheral lymphocytes disclosed a karyotype of 47,XY,+21[20]. Our case provides further evidence that these three conditions-Down's syndrome, cryptorchidism and testicular germ cell tumor-may be closely associated. To our knowledge this is the first case of mixed germ cell tumor arising in a patient with Down's syndrome and cryptorchidism.