Leiomyoma is a benign tumor of smooth muscles. Leiomyoma originating from the scrotum is a rare entity. We report a case of 53-year-old African male who presented with a 3 cm lump in the right side of scrotum. Clinically, it was provisionally diagnosed as sebaceous cyst and was excised. The histopathology showed a leiomyoma. There was no cytological atypia or mitosis. The patient also had squamous papilloma over left gluteal region.
Leiomyomas are benign tumors that originate from smooth muscles cells. Cutaneous leiomyoma are of three types: 1) tumors of arrector pili muscle (piloleiomyoma), 2) tumors of smooth muscles of blood vessels (angioleiomyoma), and 3) genital leiomyoma (from the smooth muscles of nipple, vulva, and scrotum) [
A 53-year-old African male presented to our urology clinic with chief complaints of right sided painless testicular swelling and swelling over left gluteal region since two years. He was diagnosed with hypertension and diabetes two years back and was on intermittent therapy for the same. Physical examination revealed a pedunculated firm lesion approximately three cm in diameter, on the right side of the scrotal sac. Bilateral testes were unremarkable. Inguinal lymph nodes were not palpable. In addition, a skin tag measuring 0.8 × 0.5 × 0.5 cm was noted over the left gluteal region. Systemic examination did not reveal any abnormality.
Laboratory investigations revealed normal haematological and biochemical parameters except for raised LDL (218 mg/dL; normal < 130 md/dL) and HbA1C (6.6%; normal < 6%). Renal function tests were within normal limits.
With a clinical possibility of calcified sebaceous cyst, patient underwent excision of the scrotal lesion along with that of the papilloma over left gluteal region. The postoperative course was uneventful.
Macroscopic examination of swelling in the scrotum revealed a firm, well circumscribed lesion measuring 3 cm in diameter, which on cut surface was solid, white with whorling. No necrosis or hemorrhage was noted. Microscopy confirmed a well circumscribed tumor arising from dartos (
Skin tag on microscopy showed hyperkeratosis, orthokeratosis and papillomatosis of the stratified squamous
lining epithelium. However, no koilocytosis, dysplasia or malignancy was noted. Features were of squamous papilloma.
Leiomyomas are benign tumours orginating from smooth muscle cells. Leiomyoma of skin and subcutaneous tissue can be divided into cutaneous (Pilar) leiomyoma, genital leiomyoma, or more deeply situated angioleiomyoma (vascular leiomyoma). Among the genital leiomyoma, which include those involving scrotum, vulva, or nipple, the leiomyoma of scrotum and vulva are clinicopathologically quite different, receiving little attention in the literature.
Scrotal leiomyoma is a rare tumor with <50 cases reported worldwide [
Four histopathological features are used to grade the scrotal smooth muscle tumours that include 1) size ≥ five cm in greatest dimension; 2) infiltrating margin; 3) ≥five mitotic figures per 10 high-power field and 4) moderate cytological atypia. Tumours with only one of the above-mentioned features are considered benign and those fulfilling two of the criteria are diagnosed as atypical leiomyomas while tumours showing three to four of these criteria are leiomyosarcomas [
Immunohistochemistry plays a vital role in determining the nature of spindle cells and conferring a final diagnosis. The tumour cells showed cytoplasmic positivity for SMA and were negative for S100 protein, determining their smooth muscle nature. Myofibroblasts also express SMA. In contrast to the uniform cytoplasmic expression of SMA seen in smooth muscle cells like in our case, myofibroblasts show expression of SMA only at the periphery of their cytoplasm (“tram-track” pattern). Other markers used to demonstrate smooth muscle differentiation include desmin, and caldesmon. But calponin and smooth muscle myosin are also occasionally used for this purpose. Cytoplasmic staining is observed in smooth muscle cells with all of these markers, although staining for one or more of them can be lost in poorly differentiated leiomyosarcomas.
Conventional leiomyomas and atypical leiomyomas behave in a similar fashion [
This case analysis highlights the rarity of leiomyoma in the scrotum, emphasizing two very important things. First, the clinician should be aware of occurrence of this benign smooth muscle lesion in the scrotum, to clinically suspect its presence. Second, leiomyoma must be distinguished from atypical leiomyoma and leiomyosarcoma, as the management of the latter two differs from that of leiomyoma. Atypical leiomyoma needs close surveillance post-excision, while leiomyosarcoma requires wider margin of excision and close surveillance post- excision.
We would like to thank our institute NU Hospitals, Bangalore for encouraging us to do the case analysis. Our special thanks to Dr. Venkatesh Krishnamoorthy, Dr. Prasanna Venkatesh, Dr. Maneesh Sinha and Dr. Pramod. K, Urologists of NU Hospitals, Bangalore for their clinical inputs and participation in the patient care.