A 47-year-old female presented to our institution with a six-month history of right forearm swelling. The swelling gradually increased in size and was painful. The patient went to a local hospital and performed a tissue biopsy from the swelling. The pathologist reported an inadequate sample from the biopsy. Fifteen days later, the swelling gradually increased after the surgery with a cut-through of sutures due to friable skin being accompanied by ulceration and bleeding (Fig. 1). The patient did not report any recent traumatic event or hurt to her forearm. There was no history of weight loss, loss of appetite, or any related systemic symptoms. The patient had a family history of peripheral nerve tumors in her sister. The past history was remarkable for neurofibroma in the neck and radiation of pain to the forearm, which was relieved with conservative management. The neck neurofibroma was non-progressive and did not cause any subsequent problems. There was no relevant personal history.
Examination
In addition to neurofibromas, we found a firm, oval, eight-by-five-centimeter bulge was found in the middle of the right forearm. The growth edges were diffuse, and the mass appeared tethered to the underlying muscle. The ulceration measured approximately five × four centimeters and had friable margins and well edges. (Fig. 1) The patient also reported increased soreness and paresthesia in her index and middle fingers commencing four days prior to her hospitalization. Similarly, we examined the forearm's radial and ulnar nerve involvement, but it was normal.
Diagnosis
As part of a standard laboratory evaluation, we assessed the Complete blood count, electrolytes, kidney function, liver function, and urinalysis. We also performed venous ultrasonography and an X-ray to rule out thrombosis and detect bone involvement. MRI examination of the right forearm revealed a multilobulated mass measuring 6 cm x 5.8 cm x 10.8 cm in the center of the right forearm. (Fig. 2) With a more than 180 degrees contact angle, the lesion compressed the radial artery and the median nerve posteromedially. There were no bone erosions, and the tumor reached the ulceration edges through subcutaneous planes. Ultrasound of the abdomen revealed fatty degenerative signs of grade 1. Subcutaneous neurofibromas and thyroid nodules in the right lobe were spotted during a neck ultrasound. The right axillary lymph nodes were seen on the chest CT scan, with the most prominent node measuring 3.8cm x 3.2cm x 2.9cm. A calcified hilar lymph node and bilateral lung metastasis were also found; the primary lung metastasis was 4.4cm x 3.2cm x 2.8cm.
We referred the patient for an ophthalmologic examination and MR imaging of the brain and spine to assess any occult malignancy. The test findings were negative for cancers.
Treatment
We classified rhabdomyosarcoma as stage 4 cancer according to the American Joint Cancer Committee Classification System. [6] We further categorized it as T2b N1M1 (stage 4) because of the involvement of the axillary lymph nodes and lung metastasis. The patient was scheduled for immediate primary resection of the tumor under general anesthesia and tourniquet control, following consultation with the Plastic surgery and Radiotherapy departments.
Following a meticulous dissection around the radial artery and median nerve via a modified Henry approach, the entire tumor was removed with a 2 cm safety margin. (Fig. 4) After removal, the mass appeared grey to yellow in color and gelatinous in appearance. It measured 17cmX10cmX6.5cm. The skin defect was closed with a free flap from the ipsilateral thigh. The histopathology report revealed tumor cells arranged in a herringbone pattern, with occasionally interspersed strap cells. (Fig. 7) The tumor cells were immunopositive for myogenin/myoD/desmin and negative for S100/SoX10/calponin confirming spindle cell rhabdomyosarcoma.
After the surgery, suture removal was done after twelve days without complications. (Fig. 5)The preoperative paresthesia of the patient was relieved, and she had a preserved hand function. She was advised radiation treatment for 25 days, followed by six cycles of chemotherapy. The chemotherapy cycles were scheduled every three weeks and consisted of vincristine, actinomycin-D, and cyclophosphamide (VAC) drugs. After approximately 12 weeks of standard chemotherapy, we evaluated the patients' response to treatment with an MRI. (Fig. 6) The patient's repeat MRI did not show any remnant mass. The patient did not complete the chemotherapy or report for follow-up.