Malignant melanoma of the female urethra

Abstract

Backgrounds: Malignant melanoma (MM) of urethra is extremely rare; only 84 cases have been reported in PubMed search.

Case: An 84-year-old woman presented dysuria. Physical and endoscopic examination revealed a polypoid tumor in proximal urethra, and endoscopic tumorectomy was performed. The tumor could not be seen in outer genitalia. Grossly, the tumor is brownish soft tumor measuring 15 mm × 26 mm × 23 mm. Multiple sections were made and immunohistochemical procedures were performed. Microscopically, malignant epithelioid cells with brown pigment were seen to proliferate and invade. The size of tumor was circa 13 mm × 21 mm × 18 mm. The depth of invasion was 10 mm (pT4), but it was not clear whether the marginal tissue status is positive or negative. Lymphovascular permeation seen, yet no obvious vascular invasion was noted. The brown pigment was found to be melanin by Masson-Fontana stain. Immunohistochemical study showed tumor cells were positive for vimentin, S100 protein, HMB45, Melan A, p53, and Ki67 (labeling = 85%), KIT and PDGFRA, while they were negative for cytokeratins. Genetic analysis of paraffin-embedded tumor tissue identified no mutations in hot spots of KIT and PDGFRA genes. No apparent metastatic lesions were seen after the diagnosis. The outcome of the patient is unknown because the patient was referred to a large hospital specializing in cancer treatment.

Conclusions: The author presented a very rare case of MM of the proximal urethra. The MM showed typical histochemical and immunohistochemical features. No mutations of KIT and PDGFRA were seen.

Keywords

Urethra / Female / Melanoma

References

[1] Terada T. Low incidence of KIT gene mutations and no PDGFRA gene mutations in primary cutaneous melanoma: An immunohisto-chemical and molecular genetic study of Japanese cases. Int J Clin Oncol. 2010; 15: 453-456. PMid: 20425130. https://doi.org/10.1007/s10147-010-0087-0

[2] Terada T. Malignant melanoma of the conjunctiva: A case report with examination of KIT and PDGFRA. Rare Tumors. 2012; 4: e8. PMid:22532924. https://doi.org/10.4081/rt.2012.e8

[3] Terada T. Malignant melanoma of the nasal cavity: A case report with examination of KIT and platelet derived growth factor receptor-α (PDGFRA). Rare Tumors. 2011; 3: e54. PMid:22355509. https://doi.org/10.4081/rt.2011.e54

[4] Terada T. Amelanotic malignant melanoma of the esophagus: Report of two cases with immunohistochemical and molecular genetic study of KIT and PDGFRA. World J Gastroenterol. 2009; 15: 2679-2683. PMid:19496203. https://doi.org/10.3748/wjg.15.2679

[5] Pandey PK, Vijay MK, Goel H, et al. Primary malignant melanoma of female urethra: A rare neoplasm. J Cancer Res Ther. 2014; 10: 758-760. PMid: 25313778.

[6] Cho ST, Song HC, Cho B, et al. Primary malignant melanoma of the female urethra. Korean J Urol. 2012; 53: 206-208. PMid: 22468218. https://doi.org/10.4111/kju.2012.53.3.206

[7] Terada T. Mediastinal seminoma with multiple KIT gene mutations. Pathology. 2009; 41: 695-697. PMid: 20001354. https://doi.org/10.3109/00313020903305852

[8] Terada T. Mutations and protein expression of KIT and PDGFRA genes in ipsilateral testicular seminomas: An immunohistochemical and molecular genetic study. Appl Immunohistochem Mol Morphol. 2011; 19: 450-453. PMid: 21403518. https://doi.org/10.1097/PAI.0b013e31820d2872

[9] Ide M, Koba S, Sueoka-Aragane N, et al. Mutation Profile of B-Raf Gene Analyzed by fully Automated System and Clinical Features in Japanese Melanoma Patients. Pathol Oncol Res. 2017; 23: 181-188. PMid: 27766572. https://doi.org/10.1007/s12253-016-0121-2

[10] Ascierto PA, Kirkwood JM, Grob JJ, et al. The role of BRAF V600 mutation in melanoma. J Transl Med. 2012; 9: 85. PMid: 22554099. https://doi.org/10.1186/1479-5876-10-85