Intratesticular Angioleiomyoma Open Access

Benign smooth muscle tumors arising in noncutaneous and nonuterine locations are now classified histologically as leiomyomas and angioleiomyomas; most cases formerly classified as epithelioid leiomyoma (of gastrointestinal tract, mesentery, and omentum) are now reclassified as gastrointestinal stromal tumors in the presence of an activating KIT mutation.1 Overall, benign smooth muscle tumors are extremely rare in the testis.2 Whereas intratesticular leiomyomas have been reported a few times in the English language literature (fewer than 10 cases in total),2–4 to our knowledge, intratesticular angioleiomyoma has never been reported. We therefore present a case report, including radiological and histologic features, of what we believe to be the first report of intratesticular angioleiomyoma in the English literature.

A 58-year-old man presented with a 4-month history of painless swelling of the left testicle. Clinical examination confirmed a focal enlargement of the lower pole of the testicle, which did not transilluminate. Ultrasound examination (HDI 5000 Ultrasound scanner, 12 MHz linear array probe, Philips, Best, Netherlands) revealed a discrete 1.3 × 1.4-cm intratesticular abnormality of the left testis. It demonstrated a reflectivity similar to that of normal testis and no evidence of increased vascularity (Figure 1). The features were nonspecific, and in view of the focal nature of the lesion and the age of the patient, an orchidectomy was performed.5 The patient experienced an uneventful recovery and has had no further problems to date.

The left testicle measured 5 × 4 × 3 cm, with an attached spermatic cord that was 5 cm in length. On longitudinal sectioning, a well-demarcated solid white nodule, 1.2 cm in diameter, was found at the lower pole of the testis, adjacent to the tunica albuginea; no gross hemorrhage or necrosis was evident. Histologically, the well-circumscribed tumor was formed by intertwining bundles of mature smooth muscle cells around numerous dilated vascular channels (hematoxylin-eosin staining was performed on paraffin-embedded sections of formalin-fixed tissues) (Figure 2). These vascular channels contained only small amounts of smooth muscle in their walls, which was continuous with the surrounding smooth muscle bundles. There was no microscopic evidence of hemorrhage, necrosis, nuclear pleomorphism, or mitoses. The appearances were classic for the cavernous type of angioleiomyoma. Immunohistochemistry (automated immunostainer using monoclonal antibodies to α-smooth muscle actin; Dako Corporation, Carpinteria, Calif) and the avidin-biotin complex technique (Vector Elite Kit, Vector Laboratories, Burlingame, Calif) confirmed the diagnosis with strong staining of the smooth muscle cells with α-smooth muscle actin (Figure 3). Staining for estrogen receptors, which is positive in some leiomyomas, was negative.

Angioleiomyomas are common, typically painful tumors, which occur mostly in the subcutis and deep dermis of the (lower) extremities, and to a lesser extent, of the head and trunk.1 They have also been reported at unusual sites, including the oral cavity (including within the tonsil)6,7 and auricle.8 Like the other benign smooth muscle tumor (leiomyoma), an angioleiomyoma could theoretically arise anywhere in the body from tissues containing smooth muscle. Within the scrotum, structures such as the epididymis, spermatic cord, dartos fascia, and blood vessels could be sites of origin of benign smooth muscle tumors. Numerous cases of leiomyoma arising from the tunica albuginea, tunica vaginalis testis, spermatic cord, and epididymis have been described.4 A case of angioleiomyoma and a few cases of tumorlike proliferations of the testicular adnexa (paratesticular hamartoma with angioleiomyomatous features) have been reported in the testicular adnexa, but not within the testis.9 

Intratesticular benign smooth muscle tumors, on the other hand, are extremely rare, and only a few cases of leiomyoma have been reported in the English literature to date.2 To our knowledge, angioleiomyoma occurring within the testis has never been reported. Possible sites of origin for smooth muscle tumors within the testis include the smooth muscle cells of the vascular tree and contractile cells in the seminiferous tubule walls. Radiologically, the imaging characteristics of mesenchymal tumors within the scrotum are often nonspecific,5 and therefore definitive diagnosis is achieved with histology. Since the concern is that many intratesticular lesions with nonspecific imaging features or a suspicious history are malignant, radical orchidectomy remains the treatment of choice even for this innocuous lesion.

In conclusion, we have presented the radiological and histologic features of what we believe to be the first report of an intratesticular angioleiomyoma in the English language literature.