Atypical Presentation of Rapidly Progressive Cutaneous Metastases of Clear Cell Renal Carcinoma: A Case Report

Abstract

Cutaneous metastases from clear cell renal carcinoma (ccRC) are uncommon and often indicate a poor prognosis. These metastases typically occur on the scalp, face, and trunk, and they can be difficult to diagnose due to their resemblance to benign dermatological tumors. We report the case of a 56-year-old patient with a history of ccRC (TNM stage 4) who was referred to our dermatology department with two rapidly enlarging, painful lesions on the left jawline and scalp, which had developed one month and one week earlier, respectively. On examination, the lesions appeared as well-defined, round to oval plaques with a central ulceration and a peripheral red rim, suggestive of an inflammatory appearance. Dermoscopic examination revealed a structureless pink to orange pattern, atypical central vessels, and irregular linear vessels in a corona-like arrangement. Despite the patient's stable oncological treatment for six months, pain management had recently included paracetamol, tramadol, and NSAIDs. The primary presumptive diagnosis was of cutaneous metastasis, considering the patient's history of metastatic ccRC. However, given the recent initiation of new pharmacological agents, the rapid progression of the cutaneous lesions, and their clinical presentation, alternative differential diagnoses were considered, including drug-induced reactions such as erythema multiforme or fixed drug eruption. A biopsy of the facial lesion revealed immunohistochemical positivity for CD10, CAIX, and PAX8, confirming the diagnosis of metastatic ccRC with sarcomatoid differentiation. Unfortunately, despite continued targeted therapies and palliative care, the patient's condition deteriorated rapidly, leading to death two months later. This case highlights the potential for extremely rapidly evolving cutaneous metastases from ccRC and their capacity to occasionally mimic atypical drug eruptions. Additionally, it reaffirms the poor prognosis of such metastases, as evidenced by the patient's death within two months.

Keywords: clear cell renal carcinoma; cutaneous metastases; dermoscopy; oncologic dermatology; skin metastasis mimickers.

Figure 1

Clinical aspect of the lesions. (a) A well-defined, round plaque with a targetoid appearance, characterized by peripheral erythema, a pale edematous ring, and an ulcerated center located on the left mandibular region. (b) A similar but less well-defined lesion located on the scalp.

Figure 2

Dermoscopy of the lesion on the left mandibular region. Presence of a pink to orange structureless pattern with polymorphous vasculature (dotted, arborizing, and tortuous vessels) in the central ulcerated area along with linear-irregular vessels in a corona-like distribution at the periphery.

Figure 3

Histopathological findings from the punch biopsy sample. (a) Infiltrative spindle cell proliferation, developed at the dermo-hypodermic level (hematoxylin and eosin stain, original magnification ×40). (b) Spindle cells arranged in a vaguely fascicular pattern (hematoxylin and eosin stain, original magnification ×100). (c) Fusiform cells with numerous mitotic figures, some of which are atypical (hematoxylin and eosin stain, original magnification ×400).

Figure 4

Immunohistochemistry showing a positive CAIX membranous pattern with a box-like appearance (×200 magnification).

Figure 5

Immunohistochemistry showing nuclear positivity for PAX8 (×200 magnification).

Figure 6

Proliferation index (Ki-67) was positive in approximately 35% of the nuclei of tumor cells.