Idiopathic Cervical Lymphocele Mimicking Congenital Lymphatic Malformation.

Lymphoceles are collections of lymphatic fluid that typically arise following surgical disruption of lymphatic channels, most commonly in the retroperitoneal or pelvic regions. Idiopathic presentations, especially in the cervical region, are extremely rare and may mimic congenital lymphatic malformations such as cystic hygroma and lymphangioma, complicating diagnosis. We present the case of a 30-year-old male with a neck mass that has been getting larger gradually and has caused no pain; it was associated with no previous trauma or surgery or history of infection. Imaging revealed a well-circumscribed, fluid-filled lesion that compressed adjacent cervical structures. Ultrasound-guided aspiration yielded clear lymphocyte-rich fluid, confirming the diagnosis of a lymphocele. The patient was successfully managed with bleomycin-based sclerotherapy, achieving complete resolution without recurrence over a five-year follow-up. This case emphasizes the importance of a comprehensive diagnostic approach, including clinical history, imaging, and cytological evaluation, to differentiate idiopathic lymphoceles from congenital lymphatic anomalies and highlights the efficacy of sclerotherapy as a minimally invasive therapeutic option.