A 53-year-old male patient came to the urology department for a left testicular mass. Physical examination revealed a palpation of a lesion in the upper pole of the left testicle, firm in consistency and not painful.
A testicular ultrasound scan was performed showing an area measuring 2 x 2 cm, of heterogeneous echogenicity, with multiple cystic areas, suggestive of a possible neoplasm. Tumour markers were negative. Given the high suspicion of testicular tumour, we decided to perform a radical left orchiectomy.
In the histological study of the surgical specimen, macroscopically there was a well-defined tumour, 1.8 cm in diameter, yellowish in colour and with a stony consistency. Microscopically it is made up of horny scales and nests of squamous epithelium in which "shadow" epithelial cells are recognisable. Most of this material is calcified and ossified, and a fibrous reaction is observed around the lesion, leading to the formation of a pseudocapsule that delimits the tumour. In this fibrous pseudocapsule, bundles of smooth muscle are focally identified. The testicular parenchyma shows moderate interstitial oedema. The epididymis and spermatic cord show no relevant histological alterations. The anatomo-pathological diagnosis was testicular dermoid cyst (mature testicular teratoma), pseudopilomatrixoma variant.

After orchiectomy, an extension study was carried out by chest X-ray and abdominopelvic CT scan, with no evidence of systemic extension of the disease. Testicular tumour markers (alpha-fetoprotein, beta-HCG and LDH) were negative.
The patient is asymptomatic and free of disease at present after 6 months of follow-up.