Skeletal Muscle Metastases to the Flexor Digitorum Superficialis and Profundus from Urothelial Cell Carcinoma and Review of the Literature

Abstract

Urothelial cell carcinoma (UCC) metastases to skeletal muscle are extremely rare and usually found in patients with advanced stage cancer. The most common sites of bladder cancer metastases are lymph nodes, lung, liver, and bones. Muscle is an unusual site of metastases from a distant primary cancer, due to several protective factors. We present a rare case of 76-year-old patient with metastases in the flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) muscles, 2 years after a radical cystectomy for invasive UCC of the bladder. This case is the first description of a forearm lesion, with an extensive infiltration of the volar compartments of the forearm, and the first one with a clear functional impairment.

Images – Isolated forearm soft tissue metastasis from bladder cancer

“…Most cases in the literature presented with localized and painful muscular swelling in a similar manner to our patient (6). Interestingly, as occurred in our patient, local trauma has been reported to be a risk factor potentially for development of metastases.…”

Skeletal Muscle Metastasis to Vastus Lateralis from a Urothelial Carcinoma: A Case Report and Review of Its Diagnosis and Management

“…Metastases to skeletal muscle from UCs are extremely rare and only a few cases have been reported in the English literature [9, 16–21]. Nagao et al [14] reported a case of a gluteus maximus metastasis from an adenocarcinoma of the bladder.…”

Forearm Metastases as Unsuspected First Manifestations of Lung Adenocarcinoma

“…Skeletal muscle (SM) metastases are uncommon (prevalence close to 0-0.8%). There are three theories that attempt to explain the low affinity of cancer cells to skeletal tissues: mechanical (muscle contractions could prevent the tumor to settle due to high blood pressure and variable local blood flow), metabolic (as a consequence of elevated lactate production, pH instability, and variable oxygen tension), and immunologic hypothesis (role of cellular and humoral immunity) [4][5][6].…”

“…Magnetic resonance imaging and fluorine-18-fluorodeoxyglucose positron emission tomography are the most commonly used imaging tests to differentiate muscle metastases from other lesions with similar presentations (primary sarcomas and lymphomas). Establishing the definitive diagnosis necessitates to perform a biopsy [4].…”

“…The expected survival rate fluctuates between less than 9 months to 3 years after the diagnosis of the mass. To conclude, treatment depends on the localization, clinical presentation, and prognosis of the primary tumor [4,5].…”