Primary Melanoma of Testis- A Case Report

Primary melanoma of the testis is very rare. Melanoma of testis usually occurs as metastatic tumor. Here we present a case of 54 year old man with right testicular swelling proven to be primary malignant melanoma. Patient had right scrotal swelling of six months duration. With raised LDH and unremarkable Serum β-HCG and Alpha Feto Protein level and with a suscipicion of primary testicular tumor on MRI, right inguinal orchidectomy was done. Its clinical presentation and histopathological examination is discussed here.

Testicular cancer comprises approximately 1% of all the male cancers worldwide. 1,2It is most commonly seen in younger age group. 3The incidence of testicular tumors is on rising trend in western countries. 1,3The commonest presentation of testicular tumor is painless swelling of one gonad. 1Tumors of germ cell origin account for 94% to 96% of all testicular neoplasms and sex cord stromal origin constitute 4% to 6 percent.The remaining testicular neoplasms of diverse histologic types are rare and account for 1% of testicular tumors. 2 Metastatic carcinoma to the testis is a rare finding and simulates primary testicular neoplasm. 4lanoma is a malignant neoplasm arising from melanocytes and is relatively rare. 5Melanoma metastasizing to the testis is aggressive and life threatening.The incidence of cutaneous melanoma as the primary site in metastatic testicular tumors has been reported to vary between 9% and 41%. 4 Other sites for melanoma include the oral cavities, nasal sinuses, genitalia and rectum. 5Primary melanoma of testis is extremely rare. 4ided scrotal swelling.The swelling was gradually increasing in size and was associated with pain.The pain was mild to start with and later increased.The patient did not give history of any significant illness in the past.The patient had no other findings on examination.Right scrotum was enlarged and measured 10 cm x 7 cm.The overlying skin was normal.
Right high inguinal orchidectomy was done and the specimen was sent for histopathological examination.Specimen of right testis, epididymis and spermatic cord was received in a container with formalin.Testis weighed 120 grams and measured 9 x 6 x 5 cm.Epididymis measured 2 x 0.5 cm and spermatic cord measures 7 x 2 cm.Outer surface of the testis was smooth and shiny.Cut surface showed well capsulated mass measuring 6 x 4 x 4 cm.The testis was almost replaced by the mass which was solid and cut surface was homogenous dark in colour.The mass was free from tunica vaginalis grossly.Epididymis was grossly unremarkable however the spermatic cord was thickened (fig 1).

Microscopic examination showed tumor cells arranged in sheets, fascicular pattern and occasional nested pattern (fig 2 and fig 3).
These cells shows moderate to severe pleomorphism.Individual tumor cells were oval to spindle shaped with increased nuclear to cytoplasmic ratio and cells had moderate to abundant eosinophilic cytoplasm.Few cells showed eccentric nuclei.Nuclei showed irregular nuclear rim, vesicular to coarse clumped chromatin with prominent eosinophilic nucleoli.Some of the cells showed intranuclear cytoplasmic inclusions and grooves.Binucleated cells, multinucleated giant cells and few bizarre looking cells were also noted.Stroma showed lymphocytic infiltrations and dark brown pigments.Occasional mitotic figures were seen in the mitotically active stroma.Normal testicular parenchyma showed seminiferous tubules with edematous stroma.Margins including tunica vaginalis were free of tumor.Section from the epididymis and spermatic cord were histologically unremarkable.With all this findings, the impression on histopathological examination was poorly differentiated carcinoma with differential diagnosis of spermatocytic seminoma (sarcamatoid/ anapalstic), melanoma and lymphoma.Paraffin blocks were sent for Immunohistochemistry (IHC).Result showed IHC markers MELAN-A, SOX-10, HMB-45 immunoreactive with 4+ score in neoplastic cells and IHC markers CD45, CK and SALL-4 non immunoreactive scoring 0 in neoplastic cells.The impression of IHC was suggestive of melanoma.
The patient was followed up after surgery.The wound healing was good and there were no complaints.The patient was re-examined to look for any pigmented lesions in the body elsewhere.However, no remarkable pigmented lesions were identified.The patient was referred to Oncology department but patient refused for further management.Follow up till 5 months was uneventful.

DISCUSSION
Melanoma is a neoplasm that arises from melanocytes and is increasing in incidence. 3 accounts for 1-2 % of all malignancies. 5Most of the melanoma arises from the skin.In 5-10% of cases, melanoma arises from sites other than the skin. 5Tumor metastatic to the testis accounts for 3.6% affecting elderly men.The metastasis could be from prostate, lung, urinary tract, skin (melanoma), colon or kidney. 2,4rimary melanoma arising from the visceral organ is extremely rare especially from the testicle. 3To the best of our knowledge, there were only two cases of primary melanoma of testis reported,

Primary melanoma of testis
Pudasaini S et al one on fine needle aspiration and another on histopathological examination. 5,6imary melanoma of testis is extremely rare and its existence is questionable. 4In most of the cases, it represents a disseminated disease that was not diagnosed yet. 7 Migration of melanin producing cells from the neural crest to mesodermal derivatives during embryologic development explains the presence of melanocytes in testis.This supports the possibility of a primary melanoma in testis. 5

CONCULSION
Although very rare, primary melanoma of the testis should be a consideration in a patient with scrotal pain and testicular swelling.