Poorly organized parasitic conjoined twins: report of four cases

We report four examples of parasitic conjoined twins (PCT) that created difficulties in diagnosis and treatment because of their unusual presentation and poor internal organization. Case 1 appeared as a tumor on the back containing an adrenal gland and part of the small bowel and stomach; two spines with spinal cords were present. Case 2 was similar, but mature and immature renal tissue were included and a meningocele with Arnold-Chiari type II malformation was recognized in the autosite spine. Retrospective interpretation of both cases suggested that the left lower limb and pelvis were part of the parasites. In case 3 the parasite was attached at the perineum and lower abdomen, contained a rudimentary spine in continuity with the coccyx of the autosite, and was partially covered by scalp. Case 4 presented as a limblike tumor attached at the suprapubic region. All cases were complicated by disruptions in the autosites. Surgical treatment was successful in cases 1, 2, and 3. These four anatomically poorly organized PCT are best categorized as intermediate between teratomas and the more common types of PCT.