Vaginal leiomyoma, a rare benign smooth muscle tumor, poses diagnostic challenges due to its uncommon occurrence and varied presentations, warranting a comprehensive understanding for accurate diagnosis and management.

The coexistence of breast cancer further complicated the diagnostic process in current case.

40-year-old premenopausal woman diagnosed with breast cancer underwent a PET scan, revealing incidental 18mm rectovaginal nodule. She has been referred to the gynecology clinic for further evaluation and management.

 

Diagnostic challenges encountered in the case:

 

Ct (Abdomen+ Pelvis)- Subtle contour irregularity of the posterior right aspect of the lower uterus correlates with the PET avid lesion. Exact aetiology of this is uncertain, however given FDG avidity a metastasis or primary uterine lesion are within the differential.

 

Transvaginal Pelvic Ultrasound- No sonographic correlation  for the FDG avid focus in the right adnexal region within the limits of a transabdominal study.

Declined transvaginal scan.

 

Flexibilesigmoidoscopy –normal .

 

MRI pelvis :Overall, imaging findings are not diagnostic of a specific aetiology. Whilst imaging characteristics most favour that of a fibroid, and some fibroids can demonstrate FDG avidity, this is not a common finding. In the presence of a known breast malignancy, the possibility of metastatic disease warrants exclusion. A primary vaginal malignancy is also possible but this is rare when compared to secondary malignancies of the vagina.

This case report sheds light on the challenges associated with diagnosing vaginal leiomyomas. The presence of the fibroid in a posterolateral location, coupled with the patient's history of breast cancer, added complexity to the diagnostic process. As a result, there was an initial misdiagnosis and suspicion of potential metastasis, which understandably caused anxiety in the patient. The uncertainty surrounding the diagnosis also posed a challenge for the clinician, who had to navigate through various possibilities and carefully evaluate the available information to provide accurate and appropriate care.

In conclusion, this case highlights the importance of considering vaginal leiomyomas in the differential diagnosis of vaginal masses, despite their rarity. Clinicians should maintain a high level of suspicion and include vaginal leiomyomas in future differential diagnoses to prevent misdiagnosis and ensure timely and appropriate management.