Introduction: Although most paediatric neck lumps represent common and benign disease, it is important for malignancies and other rare conditions to be considered in order to avoid potentially damaging diagnostic delay.
Case report: A seven month old boy presented to a district general hospital with an enlarging right posterior triangle neck lump. Incisional biopsy was undertaken and reported as reactive sinus histiocytosis, leading to a working diagnosis of Rosai-Dorfman syndrome. The lump grew inexorably, prompting referral to our tertiary centre for definitive management. Initial ultrasound scanning prior to referral had demonstrated a 3.5cm vascular lymph node, with smaller adjacent lymph nodes, in keeping with tuberculosis or lymphoma. Later CT scanning demonstrated a 7.5 x 8.5cm lesion, with the lack of calcification suggesting soft tissue tumour rather than a lymph node. The subsequent resection specimen demonstrated a tumour with a morphological and immunohistochemical profile in keeping with extra-abdominal fibromatosis. Definitive treatment was by surgical excision after review by the regional paediatric oncology services. The tumour was densely adherent to surrounding tissues but was felt to originate from the sternocleidomastoid muscle. Post-operatively the patient was found to have facial nerve weakness that functionally fully recovered.
Conclusion: This case highlights the importance of prompt tertiary referral in all cases of rapidly enlarging neck lumps. The clinical characteristics and treatment of extra-abdominal fibromatosis will be discussed.