Rare metastatic sites of renal cell carcinoma: a case series

Abstract

Renal Cell Carcinoma (RCC) is a lethal cancer with a propensity for wide metastasis. The patterns of metastases are not clearly defined, and patients can present with metastasis to unusual sites at the time of diagnosis of the primary tumor or years after radical nephrectomy. Individual diagnostic and surgical approaches are needed to achieve complete resection with disease-free margins, even in the presence of unusual metastatic sites, multifocality, or history of previous metastasectomy. This provides palliation for symptoms and an opportunity for meaningful disease-free and overall survival. Here we present five cases of RCC with metastasis to unusual sites (scalp, jaw, forearm, parotid, breast, and skeletal muscle). Patients were treated with cytoreductive nephrectomy and/or metastasectomy wherever feasible and/or targeted therapy. In conclusion, a high index of suspicion and accurate diagnosis is important as metastasis to unusual sites presents with atypical manifestations and may masquerade as local pathology, misleading the clinician and directly affecting prognosis and survival.

Keywords: Renal cell carcinoma; breast; jaw; metastasis; parotid; scalp.

Figure 1

A) upper jaw nodular lesion (arrow); B) ulcerated lesion in the scalp; C) H&E-stained slide at low power (x100) showing a subepithelial sarcomatoid renal cell carcinoma causing focal ulceration of overlying skin; D) post resection healthy jaw lesion; E) post resection healthy scalp lesion

Figure 2

A) right upper forearm lesion; B) high power magnification (x400) showing alveolar nests of tumor cells separated by thin fibrovascular septa. Individual tumor cells are round to polygonal with well-defined borders, clear to eosinophilic cytoplasm and ovoid hyperchromatic nuclei

Figure 3

A, B) craniocaudal view and mediolateral oblique mammography views breast; C): PET-CT axial film at breast level showing increased uptake in the right breast (arrow); D) post excision PET-CT showing no lesion in the right breast (arrow)

Figure 4

A) CT scan showing metastasis to the right trapezius muscle (arrow); B) metastasis to the right psoas (arrow); C) metastasis to left gluteus medius (arrow); D) metastasis to left hemidiaphragm (arrow)

Figure 5

A) right parotid swelling (pre-treatment) (arrow); B) MRI inT1 showing parotid involvement; C) MRI in T2 showing the tumor involvement (coronal view); D) low power magnification (x100): fibro collagenous tissue showing infiltration by a solid tumor arranged in sheets and nests; E) right parotid swelling (post-treatment) (arrow)