|Year : 2015 | Volume
| Issue : 4 | Page : 263-265
Gayatri Devi Parasa, Mark Ruth Prasanna, Satyaprakash Venkatachalam Turlapati
Department of Pathology, GSL Medical College, Rajahmundry, Andhra Pradesh, India
|Date of Web Publication||14-Dec-2015|
Gayatri Devi Parasa
Department of Pathology, GSL Medical College, Laxmipuram, Rajahmundry - 533 296, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Leiomyomas are benign tumors of smooth muscles. Leiomyoma of the scrotum, also known as genital leiomyoma, is a rare entity. Smooth muscle tumors arising in the scrotum are a specific and rare group of cutaneous tumors. We report a case of genital leiomyoma in a 55-year-old male who presented with a scrotal nodule. The mass was excised and sent for histopathological evaluation with a provisional diagnosis of sebaceous cyst. Light microscopy and immunohistochemical findings were consistent with leiomyoma.
Keywords: Cutaneous, dartos, genital, leiomyoma, scrotum
|How to cite this article:|
Parasa GD, Prasanna MR, Turlapati SV. Scrotal leiomyoma. J NTR Univ Health Sci 2015;4:263-5
| Introduction|| |
Leiomyoma is a benign tumor of smooth muscles. There are cutaneous and deep leiomyomas. Cutaneous leiomyomas are of three types depending upon their origin: Those arising from
- Arrectores pili muscles - piloleiomyomas,
- Smooth muscles of blood vessels - angioleiomyomas, and
- Nipple, areola, vulva, and scrotum - genital leiomyoma. Scrotal leiomyoma is also termed as dartoic as it arises from the dartos muscle. 
Scrotal smooth muscle tumors were first described by Fosters in 1858 and were reported to be extremely rare. These tumors arise from subcutaneous dartos muscle of the scrotum. Siegel and Gaffy in a review of 11,000 scrotal tumors found only 53 leiomyomas, which account for less than 1%. 
| Case Report|| |
A 55-year-old male presented with the chief complaint of a nodule on the right scrotum since 30 years. The swelling was insidious in onset and attained its present size over a period of time. There was no sudden increase in size, however, associated with the pain and discomfort, which was recent in onset. There is no history of fever or trauma. No other significant history. On examination it was a firm, nontender swelling of approximately 3 cm in diameter with slightly restricted mobility. The skin over the swelling was normal. The testis and epididymis were unremarkable on palpation. No ipsilateral or bilateral lymph nodes were palpable. Hernial orifices were free.
The lump was excised with a provisional diagnosis of sebaceous cyst and sent for histopathological examination.
Grossly, the specimen was a skin-covered firm nodule measuring about 2.5 × 1.5 × 1.0 cm [Figure 1]a. Cut surface is solid, grey white with whorled appearance [Figure 1]b.
|Figure 1: Gross features of excised scrotal mass: (a) Nodular mass with normal skin covering (b) Well-circumscribed oval mass with a solid, gray white, whorled cut surface|
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Microscopically, the sections showed normal skin with an underlying well-circumscribed dermal nodule composed of irregular fascicles and interlacing bundles of spindle-shaped cells (smooth muscle) localized to the dermis admixed with varying amounts of collagen [Figure 2]a. Individual cells showed elongated vesicular nuclei with blunt ends and a moderate amount of eosinophilic cytoplasm [Figure 2]b. There were occasional foci of pleomorphism and cytological atypia and no mitotic activity was noted [Figure 2]c. The periphery showed bundles of normal dartos (smooth) muscles. The tumor cells were positive for smooth muscle actin [Figure 2]d. Light microscopy and immunohistochemical findings were consistent with leiomyoma (genital leiomyoma).
|Figure 2: Microscopy showing (a) Spindle cell tumor seen in the dermis [hematoxylin and eosin (H and E), 10X] (b) Spindleshaped smooth muscle cells arranged in interlacing bundles and fascicles (H and E, 10X) (c) High power view (H and E, 40X) (d) Cytoplasmic positivity of smooth muscle actin|
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| Discussion|| |
Scrotal leiomyomas are slow-growing, painless tumors. These originate from the subcutaneous tissue or the tunica dartos muscle.  These occur most often in white men between the fourth decade and sixth decade of life. 
The time of initial presentation is wide, ranging from a few weeks to several years.  In our case, the patient came to the hospital after 30 years of initial presentation because of recent onset of pain and discomfort.
Leiomyomas of the nipple, areola, and scrotum as a group are called genital leiomyomas, which are a subset of pilar leiomyoma. Newman and Fletcher in their analysis found that nipple leiomyomas are comparable to the cutaneous leiomyomas (pilo leiomyomas) in terms of size and histology. Vulval and scrotal leiomyomas were found to be different clinicopathologically. These are rare and have not received much attention in the literature. 
Scrotal tumors are small tumors and rarely exceed 2 cm in diameter. These are graded as benign, atypical, or malignant based on four pathological features, viz, i) size ≥5 cm in greatest diameter ii) infiltrating margins iii) ≥5 mitotic figures per 10 high power fields, and iv) moderate cytological atypia. Tumors with any one of the criteria are benign, those with any two are considered atypical, and those fulfilling three to four of the criteria are diagnosed as leiomyosarcomas. 
In the present case, the tumor was 2.5 cm in its greatest dimension, with focal cytological atypia, less than five mitoses per 10 high power fields and without infiltrating margins. Hence, the tumor was considered as benign leiomyoma. Smooth muscle tumors show cytoplasmic positivity for smooth muscle actin, desmin, and are negative for S100 protein as in this case. ,,
Benign and atypical leiomyomas are similar in their behaviors and are managed by excision, whereas leiomyosarcomas need aggressive management. However, atypical or bizarre leiomyomas need long-term follow-up. 
Hence, it is very essential for a pathologist to look for criteria of malignancy, especially mitotic figures as mentioned by Newman and Fletcher who considered the presence of any mitotic activity as a criterion of malignant potential. 
Simple excision is indicated and curative for benign leiomyomas and follow-up is required for any local recurrence. A thorough investigation should be carried out for any possibility of malignancy in case of recurrence.
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[Figure 1], [Figure 2]