ESPE Abstracts

Background: Prader–Willi syndrome (PWS) is a relatively common multisystem disorder with a prevalence estimated in several studies to be in a range of one in 10 000–30 000 individuals.

Objective and hypotheses: For the first time to our knowledge, we describe the case of a couple of twin, naturally conceived, monochorionic diamniotic, both affected by PWS.

Method: The gravida 3 para 1 mother was 43, and the father 40, at the time of birth. The mother is affected by Addison’s disease and Hashimoto’s thyroiditis. At 25th week of gestation, 1st foetus displayed a neck mass detected by ultrasound. Karyotyping by G-banding of amniocentesis specimens in both fetuses showed 46XX. They were born via emergency cesarean section at 34th week. The newborns, small for gestational age, presented marked neonatal axial hypotonia, weak crying, and poor reflexes, including poor sucking, resulting in failure to thrive. They underwent genetic test which demonstrated a de novo deletion in the paternally inherited chromosome 15q11–q13 region, confirming diagnosis of PWS.

Results: The 1st twin was further evaluated with head/neck/thorax MR imaging which demonstrated a multiloculated, multicystic lesion, measuring (44×42×53 mm) with well-defined contours. The mass occupied left side of the neck, extended to the head and involved part of the posterior occipital area, parapharyngeal area, the vital blood vessel of the neck. Histologic and immunohistochemical examination demonstrated that the definite diagnosis was cystic lymphangioma. In 32nd day of life a dissection of the lymphoangioma was performed, respecting anatomical structures. Three days after the surgery, the patient showed a recurrence under the previous site of the excision. Therapeutic approach with sildenafil was tested and demonstrated no results. During the first month of life both twin presented hypothyroidism, even if they were negative at neonatal screening. Ultrasound scan detected eutopic and normal thyroid and the autoimmune screening was negative. They needed L-thyroxine treatment.

Conclusion: Well established approach in treatment of PWS is the use of the GH, on the other hand, such treatment can severe interfere with of development of lynphangioma, making the follow up a challenging task.