TFSOM DIM: Risk Factors for Choroidal Nevus Growth to Melanoma

Melanoma arising from the uveal tract (choroid, ciliary body, iris) is the most common primary intraocular malignancy. These tumors arise from nevi, but choroidal and iris nevus are extremely common, and there is approximately 1 choroidal melanoma for every 8800 choroidal nevus. Knowing which lesions are at risk of transformation can help guide patient care and improve outcomes for patients.

The mnemonic TFSOM (To Find Small Ocular Melanoma) was first introduced by Carol and Jerry Shields in 2002 as a way of predicting which choroidal nevus was most at risk for malignant transformation. The criteria was updated twice:
-- In 2009 to TFSOM-UHHD: To Find Small Ocular Melanoma Using Helpful Hints Daily
-- In 2019 to TFSOM-DIM: To Find Small Ocular Melanoma Doing IMaging

The final form emphasizes the importance of multimodal imaging with ultrasound, optical coherence tomography (OCT), and autofluorescence in the evaluation of melanocytic tumors. However, the 2009 iteration provides some practicality that can still be beneficial in evaluation of tumors, such as the absence of drusen overlying the nevus being a risk factor.

T - F - S - O - M - DIM
T = Thickness greater than 2 millimeters (measured on ultrasound)
- HR = 3.8
F = subretinal Fluid (seen on OCT)
- HR = 3.6
S = Symptomatic vision loss, 20/50 or worse
- HR = 2.3
O = Orange pigment (seen on fundus autofluorescence)
- HR = 3.1
M = Melanoma hollow, or low internal echogenicity (on ultrasound)
- HR = 2.1
DIM = Diameter greater than 5 millimeters (on fundoscopy or fundus photo)
- HR = 1.8

*Hazard ratios are in a cohort of suspicious lesions referred to an ocular oncology service for evaluation.

Further analysis of such risk factors suggested that Thickness (T), subretinal Fluid (F), and Orange pigment (O) were the most worrisome risk factors, and combinations of risk factors including these were at highest risk of malignant transformation.

Because metastasis from uveal melanoma is poorly treated, with one of the first effective treatments (tebentafusp) being introduced recently, proper evaluation of choroidal nevus and early detection of melanoma is crucial to successfully treating patients and to preserve life and sight.

TFSOM-DIM Paper: https://pubmed.ncbi.nlm.nih.gov/30608349/
Combination of Risk Factors Paper: https://pubmed.ncbi.nlm.nih.gov/30523045/
Survey of Ophthalmic Imaging in Evaluation of Choroidal Nevus: https://pubmed.ncbi.nlm.nih.gov/35606548/

All imaging used in the video is either from one of the abovementioned papers or directly from the Shields Ocular Oncology Service at Wills Eye Hospital. All imaging was obtained at the Shields Ocular Oncology Service at Wills Eye Hospital.

In this video we introduce Emily Duffner and Martin Calotti as new members of the Ophthalminute Team.

Special thanks to Carol Shields for her approval and contribution to this video.

• Category

  Eye Melanoma