Cystic hygroma of the shoulder in an 8-year-old boy: A case report

Cystic hygromas are rare congenital malformations of the lymphatic system, most commonly occurring in the head and neck regions. Involvement of the shoulder region is very rare. An 8-year-old boy presented with a painless, progressively enlarging swelling on his right shoulder since birth. Physical examination revealed a soft, cystic, non-tender mass with mild restriction of shoulder abduction. Routine laboratory tests were normal. Ultrasound showed a 4 cm thick subcutaneous cystic hygroma with septations, and a CT scan revealed a multiloculated, fluid-attenuating mass measuring 9 x 8 × 2.7 cm over the proximal humerus. The diagnosis of a right shoulder cystic hygroma was made, and the patient was scheduled for elective cystectomy. Intraoperatively, a multiseptated cystic mass measuring 18 × 18 cm with a smooth surface was found, and complete cystectomy was performed. Histopathological analysis revealed large, irregular lymphatic channels lined by flattened endothelium, separated by collagenous stroma with lymphoid infiltration, confirming the diagnosis of cystic hygroma without malignancy. The patient had an uneventful recovery and was discharged on postoperative day 3. Follow-up at 2 weeks, 1 month, and 6 months showed full recovery with a normal range of motion and no complications. Cystic hygromas of the shoulder are rare but should be considered in the differential diagnosis of pediatric soft tissue shoulder masses.