Rare Intramedullary Mature Teratoma of the Spinal Cord With Prostatic and Bulbourethral Gland Formation: A Case Report and Literature Review

Background Spinal teratomas are exceedingly rare germ cell tumors, accounting for .1%–.5% of all spinal cord tumors, with adult-onset tumors being even more uncommon. Mature teratomas consist of differentiated tissues derived from the 3 embryonic germ layers and may contain a wide variety of adult-type tissue components. Prostatic glandular tissue has been documented in only a very limited number of spinal teratoma specimens, whereas bulbourethral gland tissue has never been reported in this setting. Patient Presentation We report a 60-year-old male patient who presented with a 7-month history of low back and right lower limb pain, which progressively worsened, along with urinary incontinence for over 3 months. Lumbar magnetic resonance imaging (MRI) revealed an irregular intraspinal space-occupying lesion at the L1 level, measuring approximately 15.0 mm × 16.6 mm × 29.4 mm, which appeared slightly hyperintense on T1-weighted imaging, heterogeneous on T2-weighted imaging, and demonstrated heterogeneous enhancement on contrast administration. The patient underwent microsurgical gross total resection of the tumor. Postoperative pathological examination showed that the tumor was composed of mature tissues derived from all 3 germ layers. Endodermal derivatives included morphologically well-formed prostatic acinar structures (positive for PSA and P504S on immunohistochemistry; the preserved basal cell layer was confirmed by 34βE12 and p63 positivity, supporting a benign prostatic origin) and bulbourethral (Cowper) gland structures (clustered mucinous acini lined by cuboidal to columnar epithelium, mucin histochemistry not performed). Mesodermal derivatives included smooth muscle bundles as well as focal thin-walled vascular spaces and scattered clusters of cells morphologically resembling adrenal zona reticularis cells (polygonal cells with abundant eosinophilic or vacuolated cytoplasm containing scant, finely granular brownish-yellow pigment consistent with lipofuscin; immunohistochemical confirmation was not available, as these cell clusters were not present on deeper sections). Ectodermal derivatives consisted of glial tissue and nerve bundles. The pathological diagnosis was mature teratoma. Postoperatively, the patient's symptoms improved markedly. Conclusions To our knowledge, this is the first report of bulbourethral gland differentiation in a spinal teratoma. Other rare findings in this specimen included prostatic glands, focal vascular spaces, and cell clusters resembling adrenal cortical cells. These findings further expand the known histological spectrum of spinal teratomas and suggest that during development and migration, germ cells possess the potential to differentiate into urogenital sinus derivatives and may also give rise to other mesoderm-derived lineages. Complete surgical resection remains the mainstay of treatment, and long-term imaging follow-up is essential for monitoring recurrence.