CT and MRI Diagnosis of Adenoid Cystic Carcinoma in the Lacrimal Gland

Objective To explore the CT and MRI findings of adenoid cystic carcinoma in the lacrimal gland. Materials and Methods All 32 cases of adenoid cystic carcinoma occurring in the lacrimal gland were verified by pathological results. CT and MRI findings were analyzed retrospectively. Results 19 cases were found in the left lacrimal gland,13 in the right lacrimal gland. On CT scans, adenoid cystic carcinoma of the lacrimal gland showed ablong shape in 11 cases, irregular shape in 8 cases, flat shape in 7 cases,oval shape in 4 cases and lobulated shape in 2 cases. The lesions revealed well defined in 24 cases, irregular infiltrative edges in 10 cases. 24 cases distorted the globe. 16 cases extended into the orbital apices along the lateral orbital wall and invaded adjacent lateral rectus muscle. The optic nerves were infiltrated in 4 cases. The lesions displayed heterogeneous density in 11 cases, which were seen necrosis or (and) calcification. The lesions showed moderate to marked enhancement on postcontrast CT scans. The adjacent orbital walls demonstrated moth-eaten bony invasion in 24 cases and marked bony destruction in 3 cases. On MR T1WI, adenoid cystic carcinoma of the lacrimal gland showed hypointense signal compared to adjacent extraocular muscle in 14 cases and isointense signal in 12 cases. On T2WI, the lesions showed hyperintense signal in 22 cases and isointense signal in 4 cases. 22 cases showed heterogeneous signal intensity on MR Imaging. The lesions demonstrated moderate to marked enhancement on contrast enhanced MR images. The lesions may extend into adjacent structures such as intracranial cavity, temporal fossa, infratemporal fossa, pterygopalatine fossa,et al. Perineural spread can be found in some cases. Conclusion Most adenoid cystic carcinoma of the lacrimal gland have specific imaging manifestations, which may suggest the diagnosis. CT is the modality of first choice in diagnosis of adenoid cystic carcinoma in the lacrimal gland. MRI can demonstrate optimally the invading extent of the lesions. Both imaging modalities can provide more information for the diagnosis and therapy of adenoid cystic carcinoma in the lacrimal gland.