Sarcomatoid renal cell carcinoma with scant carcinomatous components

Primer malignant giant cell tumour of kidney: a case report

Osteoclast-like giant cell tumours of the kidney are extremely rare and usually accompanied by a conventional urothelial neoplasm such as papillary, transitional renal cell, or sarcomatoid carcinoma. Although they have morphological features similar to those of the giant cell tumours in the skeletal system, their counterparts in the urinary system show highly malignant features. Our case is the third primer malignant giant cell tumour of the kidney in the literature. The patient was a 50-year-old male and underwent nephroureterectomy for a mass of 18×14×13cm in his left kidney. However, the patient died in the second month postoperatively as a result of local recurrences and multiple distant metastases. The general condition of the patient deteriorated progressively; hence, he could not have any adjuvant therapy. Having more information about the pathological and clinical findings of these exceedingly rare tumours can help inform treatment steps.

Renal cell carcinoma with rhabdoid and sarcomatoid features presented as a metastatic thigh mass with an unusual immunohistochemical profile

Renal cell carcinoma (RCC) may metastasize anywhere in the body and sometimes the primary tumor is missing and necessitates extensive investigations to detect. In this report, we describe a case of RCC metastasizing to the thigh in a 70 year old male with a highly pleomorphic morphology suggesting a high grade sarcoma that showed unequivocal positivity for desmin directing the diagnosis for pleomorphic rhabdomyosarcoma. After completion of 33 cycles of radiotherapy, the patient developed large intraabdominal mass that showed conventional areas of RCC with immunoreactivity for CD10, CK, EMA, carbonic anhydrase IX and vimentin. The tumor cells in other areas resembled that of thigh mass which raised suspicions whether the two masses represented the same tumor or not. Surprisingly, the tumor cells of thigh mass showed diffuse positivity for CD10 and focal expression for CK, EMA and carbonic anhydrase IX. Extensive investigations failed to detect any primary renal lesions. The present case demonstrated that RCC can metastasize to virtually any body site and can have significant morphologic overlap with other non-renal neoplasms. Absence of primary origin of RCC according to radiological and operative data should not hinder the diagnosis of metastatic RCC. RCC with sarcomatoid and rhabdoid features carries aggressive behavior manifested by great metastatic potential and short survival time.

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.

Primary de novo malignant giant cell tumor of kidney: a case report

Background

Osteoclast-like giant cell tumors are usually observed in osseous tissue or as tumors of tendon sheath, characterized by the presence of multinucleated giant cells and mononuclear stromal cells. It has been reported in various extraosseous sites including breast, skin, soft tissue, salivary glands, lung, pancreas, female genital tract, thyroid, larynx and heart. However, extraosseus occurrence of such giant cell tumors in the kidney is extremely rare and is usually found in combination with a conventional malignancy. De-novo primary malignant giant cell tumors of the kidney are unusual lesions and to our knowledge this is the second such case.

Case Presentation

We report a rare case of extraosseous primary denovo malignant giant cell tumor of the renal parenchyma in a 39-year-old Caucasian female to determine the histogenesis of this neoplasm with a detailed literature review.

Conclusion

Primary denovo malignant giant cell tumor of the kidney is extremely rare. The cellular origin of this tumor is favored to be a pluripotential mesenchymal stromal cell of the mononuclear/phagocytic cellular lineage. Awareness of this neoplasm is important in the pathological interpretation of unusual findings at either fine needle aspiration or frozen section of solid renal masses.