NFB-09. Treatment of cardiac fibroma in aPTCH1-mutated Gorlin syndrome with medulloblastoma

A 2,5-year-old girl presented vomiting episodes associated with severe motor delay, macrocephaly, and distal hypotonia. Brain MRI showed hydrocephalus and a non-metastatic lesion in the posterior fossa. A pre-operative ECG showed isodifasic T waves in leads V4R and V1, follow-up was recommended. Histology after gross total resection was consistent with Desmoplastic/Nodular Medulloblastoma. At chest X-rays a bifid rib was noted, leading to the diagnosis of Gorlin syndrome (GS; c.3306 + 1G>T in PTCH1). During chemotherapy, ventricular tachycardia (VT) occurred, requiring synchronized electrical cardioversion. An echocardiogram revealed an echogenic mass of the left ventricle free wall, but normal coronaries and ventricular function. Cardiac MRI (CMR) confirmed a 21x40x38mm mass, with eccentric development and intense homogeneous enhancement, indicative of cardiac fibroma (CF). A computed tomography excluded local calcifications. Therapy with amiodarone and beta-blocker was initiated. TREATMENT STRATEGY: priority to chemotherapy vs cardiac surgery; full-dose chemotherapy, preferring drugs with minor cardiotoxicity; administration in ICU under continuous vital parameters and ECG-monitoring. Other three VTs occurred during treatment or anesthesia, resolved after electrical cardioversion (unsuccessful attempts with i.v. adenosine and amiodarone). Lacking specific guidelines concerning CF in GS, a wait-and-see approach was preferred with close tumor follow-up and regular cardiological assessment (ECG, stress-test, Holter monitoring, CMR). No further arrhythmias were recorded in a 10-year-long follow-up and CMR confirmed CF stability. Medulloblastoma has never recurred. PTCH1 variants are rarely associated with medulloblastoma (<2%). Only 3–5% of GS present CF, responsible for arrhythmias in 32%. Being non-regressing, total surgical resection is usually performed (without recurrence), with a 27-year-long median survival. When surgery risk/benefit ratio is not favorable or the patient is paucisymptomatic, the treatment plan remains unclear; probably, a conservative approach under a strict cardiological follow-up can be reasonable. In young children with syndromic medulloblastoma, a routine echocardiogram should be performed to rule out CF.