[A case of renal pelvic tumor with heterotopic bone formation].
ABSTRACT The patient was a 74-year-old man who was referred to our hospital with a complaint of left flank pain. Laboratory data were almost within normal limits and urine cytology was positive. X-ray examination revealed a calcification in the left kidney and abdominal CT scan confirmed the presence of a heterogenous renal pelvic mass which contained a calcification. Based on these examinations, a diagnosis of a renal pelvic cancer with heterotopic bone formation was made. Subsequently, left nephroureterectomy was performed. Grossly, the renal pelvis of the resected kidney was filled with a mass which had a white cut surface and bone-like tendency. Histopathologically, a poorly differentiated transitional cell carcinoma with massive bone formation was found. Fifty five cases of heterotopic bone formation in the kidney have been reported in Japan. Among the cases, 4 cases were complicated with renal pelvic tumor and our case was the second case of heterotopic bone formation complicated with a transitional cell carcinoma of the renal pelvis in Japan.
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ABSTRACT: Heterotopic ossification (HO) within tissues involved by a pathologic process is a well-recognized phenomenon. It is most frequently observed in atherosclerotic plaques, in soft tissue around joints, and in the central nervous system. Less frequently, carcinomas and some benign neoplasms will undergo heterotopic ossification. We performed a retrospective review of our experience with HO over a 10-year period to determine the frequency and tissue site distribution of heterotopic ossification. A computerized review of surgical pathology records of approximately 126,000 reports revealed 85 cases in which heterotopic ossification, ectopic bone or metaplastic bone was specifically mentioned in the surgical pathology diagnosis. Twenty-two cases were neoplasms of non-osseous tissues, and 63 cases were non-neoplastic lesions. Immunohistochemical staining for bone morphogenic proteins (BMP) 1, 4, and 6 was performed. Fourteen cases showed staining for BMP-1, 22 cases showed staining for BMP-4, and five cases showed weak staining for BMP-6. HO is a relatively infrequent finding and is more commonly seen in degenerative and reparative conditions than in neoplasms.Pathology - Research and Practice 02/2007; 203(9):633-40. DOI:10.1016/j.prp.2007.05.014 · 1.56 Impact Factor