Metastatic Malignant Melanoma Masquerading as Tolosa-Hunt Syndrome.

BACKGROUND: This case report discusses cavernous sinus metastases arising from uveal melanoma, which manifested after a 7-year remission period. The diagnosis of systemic metastatic disease was made based on ocular symptoms. To our knowledge, this is the second reported case of metastatic uveal melanoma to the cavernous sinus. The initial presentation posed challenges as it resembled Tolosa-Hunt syndrome, supported by neuroimaging and response to steroid treatment. Initially, suspicion of malignancy was low due to the 7-year remission period with no ocular or systemic signs suggestive of metastasis. However, repeat imaging was performed due to worsening symptoms upon tapering of steroid treatment. Subsequently, a biopsy was obtained which confirmed the diagnosis.

CASE PRESENTATION: A 76-year-old male with a history of left eye choroidal melanoma treated 7 years earlier and achieving complete remission on subsequent follow-ups presented with worsening pain, diplopia, and left ophthalmoplegia upon tapering steroids. An initial MRI suggested Tolosa-Hunt syndrome. A follow-up MRI revealed enlargement of the left cavernous sinus with enhancing soft tissue, extending into the orbital fissures and foramen rotundum. A left orbital-zygomatic craniotomy biopsy confirmed malignant melanoma metastasis originating from the choroidal melanoma.

CONCLUSION: This case underscores the challenge of overlapping clinical presentations and the potential for delayed recognition of metastatic malignancies in unusual sites. Therefore, it emphasizes the importance of vigilant follow-up and consideration of surgical biopsy, if feasible, to explore alternative causes.