SG11 Association between single cutaneous leiomyomas and incidence of hereditary leiomyomatosis and renal cell cancer

Abstract

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is a rare cancer predisposition syndrome characterized by multiple cutaneous leiomyomas (CLMs), uterine leiomyoma (ULM) and renal cell carcinoma (RCC). An unexpected case of fatal RCC associated with a single leiomyoma prompted us to re-examine the diagnostic criteria. Our aims were (i) to characterize the phenotypic spectrum of HLRCC and evaluate the suitability of diagnostic criteria and (ii) to analyse patients with cutaneous leiomyomas for clinical features and predisposition to HLRCC. This study was a cross-disciplinary project in genetics and dermatology. A chart review was performed of 25 patients with HLRCC seen by a clinical genetics service at a tertiary centre. An audit was undertaken of 30 histopathology reports coded as CLM from 2006 to 2021. Data about number, type and distribution of CLMs, ULMs, RCC and family history of RCC was obtained from patient files for both cohorts. CLMs were present in 72% of patients with HLRCC; 47% had multiple CLMs. Overall, 83% of female patients had ULMs, 20% of these without CLMs. The incidence of RCC was 16%. Two patients developed RCC with fewer than under five CLMs. Multiple CLMs were indicative of known HLRCC diagnosis. Three patients with multiple CLMs and ULMs were identified for referral for suspected HLRCC. Three had fewer than five CLMs and ULM. There was no family history of RCC except in confirmed HLRCC. We suggest lowering the criteria for genetic testing to encompass patients with two or more CLMs, to prevent missed or delayed diagnosis. Missed referrals emphasized the need to take a full personal and family history of CLM, ULM and RCC.