QUIZ: No. 9, 15/03/2026

 TVS

Diagnosis: Cellular angiomyxoma of the pelvis

Findings: Well-defined soft tissue mass in the paravaginal/perineal region, closely abutting the vagina and pelvic floor structures. The lesion appears iso- to mildly hypointense on T1-weighted images and heterogeneously hyperintense on T2-weighted images, consistent with a myxoid matrix. No internal fat, haemorrhage, or necrosis is seen. On diffusion-weighted imaging, the lesion demonstrates mild diffusion restriction with corresponding low ADC values, reflecting increased cellularity. Following contrast administration, the mass shows intense heterogeneous enhancement with prominent internal vascularity. The margins are well circumscribed, with no infiltrative growth, organ invasion, bone erosion, or regional lymphadenopathy.

Discussion

Ø  Cellular angiomyxoma is a rare benign mesenchymal tumor of the angiomyxoma spectrum, predominantly affecting the pelvis and perineum of adult females. It is distinct from aggressive angiomyxoma by its well-circumscribed nature, higher cellularity, and lower recurrence rate.

Ø  MRI is the modality of choice for diagnosis and preoperative planning. While both aggressive and cellular angiomyxomas show T2 hyperintensity and avid enhancement, aggressive angiomyxoma typically demonstrates infiltrative margins and a characteristic “swirled” appearance, which are absent in cellular angiomyxoma.

Ø  Mild diffusion restriction may be seen in cellular angiomyxoma due to its relatively increased cellular component, whereas aggressive angiomyxoma usually does not restrict diffusion. Correct radiologic differentiation is essential, as complete local excision is curative, and overtreatment can be avoided.The syndrome shows variable phenotypic expression; while dental and digital anomalies may be present, some patients may only demonstrate lacrimal and salivary gland abnormalities with mild hearing loss, as in this case.

Teaching pearl:

A well-defined, T2 hyperintense, intensely enhancing paravaginal pelvic mass with mild diffusion restriction strongly favors cellular angiomyxoma over aggressive angiomyxoma, which shows infiltrative margins and a characteristic swirl pattern.

P.S – Diagnosis confirmed on histopathology showing spindle cells in a myxoid stroma with prominent vascularity.