Recent-onset bloody nodule

Diagnosis: Metastatic renal cell carcinoma

The nodule initially appeared to be a benign pyogenic granuloma. In fact, a biopsy of the nodule showed a profile similar to that of a pyogenic granuloma and it exhibited granulation tissue. However, further questioning revealed that the patient had a history of metastatic clear cell renal carcinoma. (The scar was from a prior unrelated orthopedic surgery.) Immunohistochemical stains showed positive staining in the cells of interest for PAX8 and CK8, 2 markers for renal cell lineage.

Consider biopsy of a pyogenic granuloma–like lesion or one with a vascular pattern on dermoscopy in any patient with a history of malignancy

Cutaneous metastasis to the skin is a rare event, representing roughly 2% of all skin tumors.¹ Anatomically, lesions tend to appear on the head and neck in men and anterior chest and abdomen in women.² Eruptions on the back, as seen in our patient, are relatively rare. The primary source of the metastasis also is gender dependent. Melanoma is the most common source overall; but in women, breast cancer represents the large majority of cutaneous metastases³ while in men lung, large intestine, and oral cavity tumors are the most common origin.³ Renal metastases are the fourth most common cause in men.³

The clinical morphology of cutaneous metastases is protean; the most common manifestations are nodules, papules, plaques, tumors, and ulcers.² Rare manifestations include alopecia plaques, erysipelas, herpes zoster–like eruptions,⁴ and pyogenic granuloma–like manifestations, as in our case. Pyogenic granuloma–like manifestations have been described in renal cell carcinoma, breast carcinoma, acute myelogenous leukemia,⁵ and hepatocellular carcinoma.⁶

Differential includes an array of erythematous nodules

The differential diagnosis of a lesion with the appearance of a pyogenic granuloma is ­variable.

Pyogenic granulomas tend to arise over a short period of time. They are more common in children and pregnant women. Pyogenic granulomas can manifest anywhere but often are reported on the digits and extremities. Clinical history is important to ensure no history of internal malignancy.

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