Journal of Indian Association of Pediatric Surgeons
Journal of Indian Association of Pediatric Surgeons
                                                   Official journal of the Indian Association of Pediatric Surgeons                           
Year : 2019  |  Volume : 24  |  Issue : 3  |  Page : 219--221

Perianal and perineal spindle cell variant of embryonal rhabdomyosarcoma in an infant

Aditya Pratap Singh1, Kalpana Mangal2, Ramesh Tanger1, Arun Kumar Gupta1, Maryem Ansari2, Arvind Kumar Shukla1,  
1 Department of Pediatric Surgery, SMS Medical College, Jaipur, Rajasthan, India
2 Department of Pathology, SMS Medical College, Jaipur, Rajasthan, India

Correspondence Address:
Dr. Aditya Pratap Singh
Near the Mali Hostel, Main Bali Road, Falna, Pali, Rajasthan


We present a case of a perianal and perianal spindle cell variant of embryonal rhabdomyosarcoma (RMS). A 3-month-old male child presented with a firm mass in the perianal region. The mass measured 5 cm × 3 cm × 2 cm was surgically removed. Biopsy was performed; it showed embryonal RMS. Immunohistochemical (IHC) stains were performed using vimentin, myogenin, spinal muscular atrophy, and muscle-specific actin, which all showed positive results. The histological examination and IHC stains were consistent with a spindle cell variant of embryonal RMS.

How to cite this article:
Singh AP, Mangal K, Tanger R, Gupta AK, Ansari M, Shukla AK. Perianal and perineal spindle cell variant of embryonal rhabdomyosarcoma in an infant.J Indian Assoc Pediatr Surg 2019;24:219-221

How to cite this URL:
Singh AP, Mangal K, Tanger R, Gupta AK, Ansari M, Shukla AK. Perianal and perineal spindle cell variant of embryonal rhabdomyosarcoma in an infant. J Indian Assoc Pediatr Surg [serial online] 2019 [cited 2023 Nov 30 ];24:219-221
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Full Text


Rhabdomyosarcoma (RMS) is a common mesenchymal soft-tissue tumor in childhood.[1] The most common location for RMS is the head and neck region with 40% of incidence rate. The perianal and perineal location in genitourinary RMS subgroup is rare with <2% incidence rate.[2] Here, we present a case of perianal and perineal spindle cell variant of the embryonal RMS in a 3-month-old male child.

 Case Report

A 3-month-old male child presented to us with the complaint of right perianal swelling. The parent noticed the swelling for the last 1 month. The bowel habit was normal. Antenatal ultrasounds were normal. On local examination, there was a swelling in the right perianal region measured around 4 cm × 3 cm × 2 cm with overlying skin normal. On palpation, it was nontender, firm in consistency. There was no regional lymphadenopathy. Routine blood investigations were within normal limits including tumor markers (alpha-fetoprotein and beta-human chorionic gonadotropin). Ultrasound showed a 40 mm × 32 mm × 27 mm hypoechoic mass with vascularity in the right gluteal and perineal region. Magnetic resonance imaging (MRI) showed a well-marginated, lobulated lesion of 27 mm × 36 mm × 42 mm in the right perineal and buttock region and involving the right ischioanal fossa. It was solid and have few areas of necrosis and cystic. It was closely abutting the right side of the external anal sphincter and displacing the anal canal left laterally. There was no involvement of the anal canal, perineal body, and vertebra. We planned for surgical excision. There were well-defined margins. It was excised completely [Figure 1]a. Histopathology showed fascicles of the spindle cells with pleomorphism. There were round, blue cells; myxoid degeneration; and numerous rhabdomyoblasts with eosinophilic cytoplasm. There was a capsular invasion. It was suggestive of spindle cell variant of RMS [Figure 1]b.{Figure 1}

Immunohistochemistry was positive for vimentin, myogenin, spinal muscular atrophy, and muscle-specific actin (MSA) and negative for CD-34 and S-100. Immunohistochemistry confirmed the diagnosis of spindle cell variant of embryonal RMS. The patient was referred to a pediatric oncologist. The pediatric oncologist started vincristine, actinomycin, and cyclophosphamide regimens. The patient was under follow-up for the last 6 months without any recurrence and bowel habit normal.


RMS is the most common soft-tissue sarcoma in the pediatric age group before 15 years of age, accounting for approximately 3%–5% of all childhood malignancies.[3] It is a malignant tumor of immature mesenchymal cell origin.[3] The common sites of involvement are head and neck, genitourinary tract, and extremities, with perianal region being an uncommon location. They usually have regional lymph node metastasis at the presentation and comparatively poor prognosis.

RMS has four histological types: the embryological, alveolar, botryoid, and pleomorphic. Although, in all locations, the most common histological type is embryonal, for the perineal region, it is the alveolar type.[2] The histological type was embryonal in our case.

It has been shown that RMS is associated with neurofibromatosis, fetal alcohol syndrome, and congenital central system anomalies. There was not seen any such association in our case.

Embryonal RMS belongs to the class of small, round, blue cell tumors. The embryonal RMS makes up about 60%–70% of RMS cases.[3] RMS may be present at birth; 1%–2% of all cases are congenital with intrauterine origin. There is no racial predilection. It is more frequent in males than in females with a ratio of 1.3:1. Although it may arise anywhere in the body, it has a predilection for the head and neck area, genitourinary tract, and extremities.[3] However, in our case, it is seen in the perianal and perineal regions, and the parent noticed the swelling at the age of 2 months. It may be present since birth. Our case was also a male child.

Age of the patient, location of the tumor, histopathologic features, and metastatic status are the important prognostic factors for RMS. The primary imaging modality is MRI.

They may occur as apparently well-defined, encapsulated, and perineal mass, which may be misdiagnosed as condyloma acuminata, fibromas, or fibromyosarcoma. Sometimes, they may present with reddish discoloration caused by hemorrhage or necrosis and abscess.

Fine-needle aspiration cytology is a simple and useful procedure for making an early diagnosis and helping clinicians for prompt intervention. Definitive diagnosis is based on histopathology.

In children, the lesion originates from the primitive mesenchymal cells with marked cellular distortion and myxomatous elements. They are of embryonic origin arising from the immature myeloblasts. There was a better demarcation plane during surgery as well as in histopathological examination. The role of immunohistochemistry is of utmost importance, which helps in excluding from other round cell tumors.

The most useful immunohistochemical markers available today are the antibodies against desmin, MSA, myoglobin, wide spectrum keratin, epithelial membrane antigen, S-100 protein, neuron-specific enolase, MIC-2, p-53, MyoD, and myogenin, with the most incidence rate of positivity for desmin, MSA, and myoglobin. The degree of positivity obtained depends on the level of differentiation.

Embryonal RMS generally responds very well to chemotherapy. However, a prolonged follow-up is necessary to evaluate the outcome of treatment. Good response to chemotherapy allows surgery to be done less aggressively if needed. The use of radiotherapy is restricted by very high risk of side effects.[3] No details of the management of the radiation therapy are available.

There is no established treatment strategy for RMS of the perineum or anus, particularly in the Intergroup Rhabdomyosarcoma Staging reports, as these locations are rare. The few cases of perianal RMS that have been reported have been associated with frequent sphincter disorders or anal ulcerations.[4] Wide, first-line curative surgery is possible, but causes loss of sphincter function. Multimodal treatment may preserve sphincter function and achieve remission without major complications and should not be withheld because of young age. A perianal site is unusual and is associated with high risk and a low cure rate.[4]

Our case is unique because it is located at the unusual perianal site, embryonal type, without any metastasis, on any associated systemic anomalies, without any sphincteric dysfunction, and may be antenatal.


Although the perianal/perineal region is rare for RMS with no particular imaging findings, it should be considered in the differential diagnosis for perianal/perineal tumors in children.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.


We would like to acknowledge Dr. Neelam Dogra, Anesthesiologist, Senior professor, SMS Medical College, Jaipur, Rajasthan, India.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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