In this issue of the journal Iafollo et al.[1989] plead for early recognition of the congenital hypothalamic hamartoblastoma (Pallister-Hall) syndrome in patients with anal and hypothalamic but without readily evident other morphologic manifestations. Their success with early effective surgery and endocrine therapy prompts our report of two patients who survived for a considerable time only to die of the tumor. The apparent timing of the insult again suggests a teratogen. Without dramatic physical changes nor the severe neonatal distress seen in our first cases [Hall et al., 19801, delayed recognition of the tumor and failure to intervene early may impair an otherwise successful outcome. Iafollo et al. point out that magnetic resonance imaging is the most valuable diagnostic tool (CT scan missed the tumor in their patient 2 as in our patient 2 reported here). Also their patient has not yet had a tumor recurrence as might be expected. In addition, a third case with a constellation of many of the Pallister-Hall malformations, but without the hamartoblastoma, is reported. A large ll zyxwvutsrqpo x 4 x 3 cm arachnoid cyst appears to have triggered the development of at least some of the condition.