Primary Mucosal Melanoma Mimicking High Grade Urothelial Carcinoma: A Potential Diagnostic Pitfall


Primary Mucosal Melanoma Mimicking High Grade Urothelial Carcinoma: A Potential Diagnostic Pitfall


Dr Christopher Julien, Dr. Xiaowei Xu, Dr. David Elder, Dr. Lauren Schwartz, Dr Norge Vergara, Dr Karen Gustafson, Dr Priyanka Karam, Dr. Priti Lal

Hospital of the University of Pennsylvania, Department of Pathology


International-Journal-of-Case-Reports-2d code

Primary malignant melanomas of the genitourinary tract are rare, representing < 1% of all cases of melanoma1,2. We report a case of a 68-year-old female patient with primary malignant melanoma of the urethra with morphology mimicking that of high grade papillary urothelial carcinoma. The patient presented following a workup with an outside urologist that revealed a urethral mass. The patient complained of urinary incontinence and pelvic pain at initial presentation. A CT scan of the abdomen & pelvis revealed a soft tissue density within the vaginal vault, consistent with urethral cancer. A cystoscopy and urethral excisional biopsy was performed. Histologic examination of the specimen revealed an invasive tumor composed of epithelioid cells with prominent eosinophilic cytoplasm forming papillary structures. However, the tumor cells were negative for CK7, CK20, GATA 3 and Pancytokeratin and positive for S-100, SOX 10 and Melan A. The case was ultimately diagnosed as malignant melanoma.


Keywords: Melanoma, Primary Mucosal Melanoma, High Grade Urothelial Carcinoma, Urogenital


Free Full-text PDF


How to cite this article:

Christopher Julien, Xiaowei Xu, David Elder, Lauren Schwartz, Norge Vergara, Karen Gustafson, Priyanka Karam, Priti Lal. Primary Mucosal Melanoma Mimicking High Grade Urothelial Carcinoma: A Potential Diagnostic Pitfall. International Journal of Case Reports, 2020 4:148 . DOI: 10.28933/ijcr-2020-06-2105


References:

1. Bhutani N, Kajal P, Pawar D. Primary malignant melanoma of the female urethra: Report of a rare neoplasm of the urinary tract. Int J Surg Case Rep. 2017;41:319-322. doi:10.1016/j.ijscr.2017.11.001
2. Gupta R, Bhatti SS, Dinda AK, Singh MK. Primary melanoma of the urethra: a rare neoplasm of the urinary tract. Int Urol Nephrol. 2007;39(3):833-836. doi:10.1007/s11255-006-9086-5
3. Mihajlovic M, Vlajkovic S, Jovanovic P, Stefanovic V. Primary mucosal melanomas: a comprehensive review. Int J Clin Exp Pathol. 2012;5(8):739-753.
4. Bassily NH, Vallorosi CJ, Akdas G, Montie JE, Rubin MA. Coordinate expression of cytokeratins 7 and 20 in prostate adenocarcinoma and bladder urothelial carcinoma. Am J Clin Pathol. 2000;113(3):383-388. doi:10.1309/G1RA-EU9X-X6VV-3W79
5. Sanchez AA, Wu TT, Prieto VG, Rashid A, Hamilton SR, Wang H. Comparison of primary and metastatic malignant melanoma of the esophagus: clinicopathologic review of 10 cases. Arch Pathol Lab Med. 2008;132(10):1623-1629. doi:10.1043/1543-2165(2008)132[1623:COPAMM]2.0.CO;2
6. El-Safadi S, Estel R, Mayser P, Munstedt K. Primary malignant melanoma of the urethra: a systematic analysis of the current literature. Arch Gynecol Obstet. 2014;289(5):935-943. doi:10.1007/s00404-013-3130-3
7. Pacella M, Gallo F, Gastaldi C, Ambruosi C, Carmignani G. Primary malignant melanoma of the bladder. Int J Urol. 2006;13(5):635-637. doi:10.1111/j.1442-2042.2006.01375.x