PMC6873277_01
Lacrimal sac mass (E) on the left side on computed tomographic scan (A) at
the initial presentation in a 78-year-old man. About 1 month after
dacryocystectomy, subcutaneous pigmented lesions (F) were noted and
whole-body 2-[18F]fluoro-2-deoxy-D-glucose positron emission
tomography fused with computed tomography (PET/CT) showed 2 high-uptake
sites at the levels of medial canthus (SUVmax = 10.29, B) and
nasolacrimal duct (SUVmax = 15.38, C). About half a year after
oral dabrafenib (Tafinlar) 300 mg daily plus trametinib (Mekinist) 2 mg
daily, the subcutaneous lesions subsided (G) with unchanged conjunctival
pigmentation on the lacrimal caruncle (H) and no abnormal uptake on PET/CT
(D).
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A 78-year-old man was presented with 10-month history of waxing and waning painless swelling of the lacrimal sac on the left side (Figure 1E). The pigmentation was noted on the lacrimal caruncle on the left side (Figure 1H). Computed tomographic scan showed a 1-cm-sized round homogeneous mass with no bony change on the left lacrimal fossa (Figure 1A). One month later, he developed subcutaneous pigmented bumpy lesions surrounding the medial canthus (Figure 1F), and whole-body 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography fused with computed tomography (PET/CT) showed 2 high-uptake sites (SUVmax = 10.29 and 15.38) at the levels of the medial canthus (Figure 1B) and nasolacrimal duct (Figure 1C), with no abnormal uptake found in the other sites of the body. In half a year, the subcutaneous and nasolacrimal ductal recurrent lesions resolved (Figure 1G), and PET/CT showed no abnormal uptake in the orbit on the left side (Figure 1D), with no abnormal uptake at other sites of the body. Conjunctival pigmentation in the lacrimal caruncle on the left side (Figure 1H) remained unchanged in comparison with the initial visit.
Pathology of lacrimal sac melanoma. (A) Large epithelioid cells with abnormal
nuclei arranged in irregular strands and foci. (B) Small lymphocytes
infiltrated as a focus among large neoplastic cells. The neoplastic cells
are negative for keratin AE1/AE3 (C), and positive for cocktail-mix
antibodies against tyrosinase, melan A (MART-1, melanoma antigen recognized
by T cells-1), and HMB45 (D). Scale bar = 200 microm in A, C, and D. Scale bar =
50 microm in B.
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The entire lacrimal sac was infiltrated with large epithelioid cells with anomalous nuclei, sometimes, multinucleated large cells in a diffuse pattern (Figure 2A and B). A (MART-1, melanoma antigen recognized by T cells-1), and HMB45 (Figure 2D), but negative for cytokeratin AE1/AE3 (Figure 2C) or CAM5.2. A cluster of small lymphocytes were noted among the large neoplastic cells (Figure 2B).