1Senior Resident, Department of Pathology, IGIMS, Patna
2Associate Professor, Department of Biochemistry, IGIMS, Patna
3Consultant Physician, Metro City Diagnostics and Research Centre, Patna
4Additional Professor, Department of Pathology, IGIMS, Patna
5Senior Resident, Department of Pathology, IGIMS, Patna
Malignant melanoma could present with metastasis with unknown primary (MUP) and this happens in 2–3% according to the studies. Around 90% of melanomas have cutaneous origin, but still there are melanomas that could be found in visceral organs or lymph nodes with unknown primary site. Spontaneous regression of the primary site could be an explanation.
We report a 58-year-old Indian male who presented with multiple swelling in both side in the inguinal region. Firstly FNAC was done and then surgery was done.FNAC and biopsy both showed metastatic malignant melanoma. No cutaneous lesion was identified by history or physical examination. Work up could not detect the primary lesion and patient was started on radiotherapy and immunotherapy.
We present a case of malignant melanoma of unknown primary presenting in an unusual place which is the inguinal lymph node. Theories try to explain the pathway of development of such tumors and one of the theories mentions that it could be a spontaneous regression of the primary cutaneous lesion. Another theory is that it could be from transformation of aberrant melanocyte within the lymph node. Prognosis is postulated to be Better in this case than in melanoma with a known primary.
Malignant melanoma accounts for 1–3% of all malignancies with an increasing incidence being seen worldwide(1). Malignant melanoma with unknown primary(MUP) accounts for approximately 2 to 3% of all melanomas and was described first in 1952(1). Contemporary criteria for the diagnosis include 1) metastatic melanoma confirmed clinically, andhistologically. 2) the absence of a previous cutaneous tumor, pigmented or not, destroyed or excised without histologic examination; and 3) exclusion of unusual primary sites, including urogenital, otolaryngologic, or ophthamologic sites2. The relatively favorable long-term survival of patients with MUP in previously conducted studies have suggested that patients with MUP have a natural history that is similar to (if not better than) the survival of many patients with stage III disease. Therefore, patients with MUP should be treated with an aggressive surgical approach with curative intent and should be considered for stage III adjuvant therapy protocols(3). In about 5–15% of cases, metastatic melanoma is detected in the absence of an identifiable primary tumor. In these cases it is generally believed that the primary tumor has regressed(4–6).
Malignant Melanoma, FNAC, Melanocyte, MUP
