Seminoma testis with contralateral vanishing testis: A rare case

A 36-year-old gentleman presented with complaint of painless swelling of right testis since 2 years. There was no previous history of trauma, fever, weight loss or any infection. On palpation right testis was diffusely bulky and hard, occupying left hemiscrotum also. Left testis was not felt separately.

On USG, large heterogenous intratesticular mass seen completely replacing right testis, from which epididymis was not seen separately. Spermatic cord was also thickened. Left hemiscrotum was empty.

Findings of USG was confirmed on MRI pelvis by using T1WI, T2WI, T1FS, DWI/ADC, SWI and postcontrast T1FS sequences in different imaging planes. The lesion was heterogeneously hypointense on both T1WI and T2WI with areas of restriction and blooming within. MRI also showed indistinct tunica in the region of mediastinum. The epididymis was also bulky, heterogenous with restricted diffusion s/o invasion. On postcontrast images lesion was showing homogenous enhancement.

Left testis was not seen in hemiscrotum nor in abdomen, however spermatic cord was seen in inguinal canal, and thus we gave diagnosis of vanishing testis.

CT abdomen and chest showed no significant findings except some equivocal sub centimetric lymph nodes in retroperitoneum.

Literature on vanishing testis is scant as only limited cases have been reported globally. On imaging, we found left spermatic cord with gonadal vessels but testis was not visualised in hemiscrotum or any other ectopic location (Fig 1). Also on enquiring from the patient, we come to know that patient has single testis since birth. Clinically, this syndrome is regarded as testicular vanishing syndrome or testicular regression syndrome (TRS) [1]. Regarding etiopathogenesis, variable theories are given but most accepted one is early intrauterine life ischemic event which is corroborated histologically with presence of dystrophic calcification [1].

In the US, seminoma is the most common subtype of testicular cancer, comprising 55% of cases with median age at diagnosis is 35-39 years [2]. Risk factors for testicular cancer are personal history of a testicular germ cell tumour, Untreated cryptorchidism, infertility, family history, environmental exposures, racial factors etc.

The first step in evaluation of painless scrotal mass, is to determine the origin of mass that is testicular or extra-testicular [3]. It is because in this age group most of the extra testicular masses are benign (cysts, cyst-like lesions, and other benign entities) and whereas testicular masses are malignant. On MRI, seminomas usually appear as multinodular tumours of uniform signal intensity that are hypointense on T2-weighted images with T2 hypointense fibrovascular septa showing greater enhancement than tumor tissue after gadolinium administration (Fig 2,3,and 4) [4]. Tumours that were markedly heterogeneous both on unenhanced and contrast-enhanced images were indicative of a non-seminomatous neoplasm [2].

Moderate heterogeneity was also seen in our case, might be due to its large size and long-standing duration (from past 2 years).

Our patient underwent radical orchiectomy and seminoma was confirmed on histopathology. Left testis was not seen during surgery, however, cord was identified in inguinal canal, so vanishing testis was confirmed.

So with this case, we learned that presence of spermatic cord and gonadal vessels with absence of testis is suggestive of vanishing testis and multinodular, homogeneous mass with fibrovascular septa favours seminoma (whereas heterogeneity favours non-seminomatous neoplasm).

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