PTL is an aggressive extranodal lymphoma and is usually seen in the elderly age group, but recently it has shown an increased incidence in the younger age group.[3
] This could be attributed to the increased prevalence of HIV infection.[3
] Another potential cause for incidence in younger age, could be that the immunophenotypic characterization of testicular tumors in recent years has led to a better recognition of PTL and less frequent misinterpretation as germ cell tumor.
PTL usually presents as a unilateral testicular mass of variable size. Grossly, lymphoma is seen as a solid, homogenous, grey-white mass with a lobulated appearance replacing the testis. Bilateral involvement can also occur at presentation and has been reported in 18% of cases.[4
] The tumor usually also shows contiguous spread to the tunica albuginea, rete testis, epididymis and spermatic cord. In one large series, involvement of the epididymis and spermatic cord was seen in 60% and 39% of cases respectively whereas involvement of the tunica albugenia is very rare.[2
Histologically, diffuse large B-cell lymphoma (DLBCL) is by far the most common type of NHL. Other reported types include follicular lymphoma, plasmacytoma, and lymphoblastic and burkitt-like lymphomas.[2
] DLBCL shows obliteration of testicular parenchyma by neoplastic cells arranged in solid sheets and separated by thin fibrous tissue. At the periphery, the tumor may show a distinctive intertubular growth pattern with splaying of seminiferous tubules by irregular aggregates, clusters and cords of tumor cells. The tumor cells are large with ill-defined cell membrane, and variable amounts of non-vacuolated cytoplasm. Nuclei are pleomorphic with irregular and twisted nuclear borders, fine chromatin and sometimes inconspicuous nucleoli. Lymphocytes, plasma cells, eosinophils and histiocytes may be seen, especially at the periphery of the tumor. Single-cell necrosis may be seen, but large foci of necrosis are much less frequent.[5
The major mimickers of PTL are seminoma and embryonal carcinoma. Seminomas show tumor cells arranged in sheets with fibrous septa in between showing lymphocytic infiltration. The tumor cells are usually large, have a distinct cell membrane with abundant clear cytoplasm with a centrally placed large nucleus and one to two prominent nucleoli. Embryonal carcinoma typically has a more pleomorphic appearance with more abundant cytoplasm and prominent areas of hemorrhage and necrosis.[5
] Immunohistochemistry is essential in differentiating these tumors, as treatment options in these entities also vary.
Recently, immunohistochemistry has led to further classification of DLBCL into two groups—non-germinal center type which carries a poor prognosis than the germinal center type which carries a better prognosis.[6
] The two different categories can be identified by the expression pattern of CD10, Bcl-6 and MUM1. Germinal-center DLBCL expresses CD10 and Bcl-6. Non-germinal center DLBCL is negative for CD10 and positive for MUM1. The majority (89%) of primary DLBCL belong to the non-germinal center type and have a high proliferative activity.[6
Testicular lymphoma has an aggressive clinical course and can frequently involve extranodal sites at presentation and at relapse.[2
] PTL is reportedly associated with involvement of the skin and subcutaneous tissue in 6-13%, Waldeyer's ring in 4-6% and CNS in 3-6%. The CNS and Waldeyer's ring are common sites of involvement at relapse and carry a poor prognosis. Less common sites are the lung, bone, liver, GIT and nodal sites, especially the paraaortic lymph nodes.[2
Testicular tumor metastasizing to the inguinal node is unusual, and is possible only when there is scrotal involvement. The primary path for testicular cancer metastasis is to the retroperitoneal lymph nodes. The inguinal lymph nodes are not usually involved, unless the tumor has invaded the scrotum, or a scrotal incision was made during biopsy or orchiectomy, or there was prior scrotal surgery such as repair of a hydrocele or a varicocele. In the present case, we believe that inguinal node involvement could be because of a rupture of testicular lymphoma which has spread to the parietal layer of the tunica vaginalis and scrotum, which is an unusual case. The patient was subjected to chemotherapy and follow-up for three months, wherein the inguinal swelling reduced in size. However, the patient was lost for further follow-up.
Rupture of lymphoma has been reported commonly in the spleen and is sometimes the presenting symptom.[7
] Rare sites of rupture include the small intestine and heart.[8
] An extensive search of the literature did not reveal any case of testicular lymphoma with rupture. However, one case of testicular lymphoma with inguinal node swelling without other site involvement has been reported, but the reason for metastasis has not been discussed.[9
] The present case emphasizes an unusual presentation of testicular rupture with inguinal node involvement.