Pleomorphic adenoma of the lacrimal glands

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Pleomorphic adenomas of the lacrimal glands, also known as benign mixed tumors (BMTs), are the most common lacrimal gland tumors.

Clinical presentation

  • slowly progressive and painless proptosis, with inferomedial displacement of the globe
  • visual disturbance possible with large tumors
  • sudden onset of pain may indicate malignant transformation

Radiographic features

CT
  • solid or heterogeneous
    • highly cellular and smaller tumors are more homogeneous
    • less cellular and larger tumors may be more heterogeneous from mesenchymal stroma, cystic degeneration, necrosis, or serous/mucous collection
  • well-circumscribed
  • round or oval in shape
  • occasional punctate calcifications
  • bony remodeling of the lacrimal fossa
  • moderate to marked contrast enhancement
MRI
  • T1: iso- to hypointense to muscle
  • T2: iso- to hyperintense to muscle
  • T1 C+: moderate to marked enhancement
  • heterogeneity may vary with size/cellularity as with CT

Treatment and prognosis

Complete excision is curative, with an excellent prognosis. Incomplete excision is associated with high rates of recurrence.

Risk of malignant transformation is low but cumulative over time.

Differential diagnosis