A Case of Primary Malignant Melanoma of the Nasolacrimal Duct

Abstract

Malignant melanoma of the nasal cavity and paranasal sinuses is an extremely rare disease, with only a few reported cases originating from or extending into the nasolacrimal duct. Multimodal treatments, including surgery, radiotherapy, chemotherapy, immunotherapy, and immune checkpoint inhibitors, have been attempted; however, the treatment outcomes remain unsatisfactory. We herein report a case of primary malignant melanoma of the nasolacrimal duct, which was successfully managed through complete en bloc resection of the nasolacrimal duct along with the surrounding bony structures, lacrimal sac, and puncta, followed by adjuvant radiotherapy and administration of immune checkpoint inhibitors. This multidisciplinary approach resulted in a favorable clinical course. Due to the rarity of mucosal malignant melanoma, many aspects of the disease remain unclear, and further evidence is warranted.

Keywords: immune checkpoint inhibitors; mucosal malignant melanoma; nasolacrimal duct; postoperative radiotherapy; surgery.

Figure 1. Preoperative endoscopic, CT, and MRI findings showing tumor extension from the inferior nasal meatus to the lacrimal sac

(a) nasal endoscope, (b) coronal CT scan, (c) coronal MRI, and (d) axial CT scan. The tumor extended from the inferior nasal meatus along the nasolacrimal duct, reaching the lacrimal sac. Arrow: tumor, CT: computed tomography, MRI: magnetic resonance imaging

Figure 2. Intraoperative views demonstrating en bloc resection of the tumor via right lateral rhinotomy and subsequent reconstructive procedures

(a) Skin incision (arrow) showing en bloc resection including the lacrimal puncta and overlying skin. (b) Tumor and resection margins (photograph). (c) Post-resection view; the black arrow indicates exposed fat after excision of the medial canthal conjunctiva, the white arrow indicates the maxillary bone wall resection line, and the white arrowhead indicates the tumor. (d) Schematic of the bone resection line; the red line indicates the planned surgical margins, including the lacrimal sac, medial orbital wall, and frontal process of the maxilla. The medial canthal conjunctival defect was not repaired, as it did not cause ocular displacement (Image Credit: Authors, using Microsoft PowerPoint and Paint 3D for Windows). (e) Reconstruction using glabellar and malar flaps after tumor and bone resection. Right lateral rhinotomy was performed with en bloc resection of the skin, lacrimal puncta, tumor, and surrounding bony structures, followed by reconstruction with glabellar and malar flaps.

Figure 3. Histopathological and immunohistochemical findings confirming primary malignant melanoma of the nasolacrimal duct

(a) Nasolacrimal duct level – gross appearance (left), H&E staining (×2, middle), and H&E staining (×20, right). (b) Inferior nasal meatus level – gross appearance (left) and H&E staining (×2, middle); red line indicates tumor (gross), black arrow indicates tumor (histology). A black, polypoid lesion protruding into the nasal cavity was observed. H&E staining showed atypical spindle- to polygonal-shaped cells with eosinophilic cytoplasm and prominent nucleoli located beneath the ciliated columnar epithelium. The tumor was also present beneath the nasolacrimal duct mucosa, whereas the inferior nasal meatus was spared, suggesting primary origin from the nasolacrimal duct. (c-f) Immunohistochemical staining for HMB-45 (c), Melan A (d), S100P (e), and MIB-1 (f). Tumor cells were positive for HMB-45, Melan A, and S100P, with an MIB-1 labeling index of approximately 30–40%. H&E: hematoxylin and eosin

Figure 4. Postoperative follow-up CT images three years after surgery showing no evidence of recurrence

(a) Axial view and (b) coronal view. No recurrence is observed in either image. CT: computed tomography