A 22-year-old male patient, with no history of interest apart from being a regular smoker of marijuana, came to the emergency department reporting enlargement of the left scrotal sac after physical exertion 24 hours earlier, with pain of sudden onset and moderate intensity. No fever or micturition syndrome, nor irradiation of the pain. There was no associated neurovegetative cortex or alterations in bowel rhythm.
On physical examination he was apyretic and normotensive, with good skin and mucous membrane colouring. The abdomen is soft and depressible, non-painful and without masses. The renal fossae are free. The right testicle showed no alterations while in the left testicle there was a stony tumour 2-3cm in diameter, non-mobile, in the upper pole of the left testicle, with negative transillumination.
Laboratory tests showed no abnormal parameters.
In the testicular ultrasound, both testicles showed a normal echostructure with preserved Doppler flow, showing an extratesticular solid mass, in contact with the upper pole of the left teste of 25mm with vessels in its periphery.
The patient was admitted to complete the study and identify the lesion.
Following the oncological protocol, the preoperative staging was completed with chest X-ray, testicular tumour markers and general analyses, and abdominal-pelvic CT scan without finding any pathological alterations in any of the tests.
A surgical exploration was then performed via the inguinal route where a slightly dented left paratesticular mass with smooth curves, pearly and stony in consistency, easy to dissect with a cleavage plane between it and the upper pole of the left testicle and spermatic cord on the same side, with some venous vessels in its periphery, was observed. A perioperative biopsy was taken which showed fibrous tissue with no malignant cellularity. The lesion was excised, leaving the teste and epididymis intact, sparing the patient a radical orchiectomy.
With an uneventful postoperative period, he was discharged two days after the operation.
The anatomopathological report of the surgical specimen was a solitary fibrous tumour of the tunica vaginalis.

In the postoperative control two years after the operation, the patient is asymptomatic with no evidence of recurrence and free of disease.