Abstract
Purpose :
The phenomenon of in-transit metastases (IM) has been well described in skin melanoma (SM) and is associated with higher stage disease and eventual lymph node and distant metastases. Locoregional metastases outside of lymph nodes in conjunctival melanoma (CM) have not been well described. We hypothesize that like SM, CM can display IM, which likely results in a more aggressive clinical course and may be underrecognized by ophthalmic pathologists and ophthalmologists.
Methods :
A retrospective observational study identified three patients with IM in the setting of CM, either at the time of initial diagnosis or subsequently. Review of clinical data including slit lamp photography and imaging studies, as well as hematoxylin/eosin and immunohistochemical stained sections, was undertaken.
Results :
Three patients aged 39, 41 and 95 years were diagnosed with CM. In one patient, a subepithelial nodule of melanoma arose from the superior tarsal conjunctiva one year after complete excision of a recurrent melanoma of the inferior bulbar conjunctiva. In the other two patients, IM presented as large discrete nodules mimicking pyogenic granuloma which were entirely separate from a synchronous primary CM or melanoma in situ. In addition to no overlying in-situ component, metastatic foci were also cytomorphologically distinct, with marked epithelioid cell atypia and loss of expression of some melanocytic markers. All patients were treated with immune checkpoint inhibitors after excision. Two patients had local recurrences and one ultimately underwent exenteration. Multimodality imaging showed no lymph node or distant metastases at the time of this report.
Conclusions :
IM of CM occur as they do in the skin. Histopathologically, the metastatic foci may show more atypical cytomorphology than the primary tumor and do not display an overlying intraepithelial component. Caution must be taken to avoid misdiagnosis as recurrence and/or second foci of invasive disease.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.