Intramuscular hemangioma with hemorrhagic transformation arising from paraspinal muscles of posterior neck: A case report

RATIONALE: Hemangiomas are usually found in cutaneous or mucosal layers, less than 1% of hemangiomas develop in skeletal muscles. Intramuscular hemangioma (IH) in the head and neck areas is relatively infrequent, accounting for 15% of IH. Most of them are identified as a benign mass, and rapid changes in size or internal bleeding are rare. PATIENT CONCERNS: A 60-year-old female patient presented with a 2-week history of sudden onset posterior neck pain. There was no neurological deficit except limited neck motion due to pain. The palpable mass was noted on the paraspinal muscles of cervicothoracic junction, which was located midline to left side portion with tenderness. DIAGNOSES: Magnetic resonance imaging demonstrated a round shaped, multi-lobulated, and well-defined mass lesion (4.1 × 2.6 × 0.9 cm) embedded from the inter-spinous space of T1-2 to the left paraspinal muscles. The lesion was iso-intense on T2-weighted images (WI), iso- to slightly low-intense on T1-WI, heterogeneous enhancement of intra- and peri-mass lesion on contrast-enhanced T1-WI. Vascular structures presented as signal voids were identified internally and around the mass lesion. Histological examination revealed a mixed-type hemangioma. INTERVENTIONS: The mass was removed completely including some of the surrounding muscles where boundaries were unclear between the mass and surrounding muscles with ligation of peritumoral vessels. Dark-brown colored blood was drained from the ruptured tumor capsule during the dissection. There was no bony invasion. OUTCOMES: The preoperative symptoms improved immediately after the operation. There is no residual or recurrence lesion by the 15-months follow-up. LESSONS: IH with hemorrhagic transformation in the head and neck is extremely rare. In the case of intramuscular tumors accompanied by a sudden onset of severe acute pain, we recommend considering a differential diagnosis of IH with hemorrhagic transformation. Complete resection of the tumor mass including surrounding muscles is required to prevent recurrence.