Antti Koivusalo1, Risto Rintala2, Mikko Pakarinen2
1Childrens` Hospital, Helsinki, Finland. 2ChildrensĀ“ Hospital, Helsinki, Finland


Background and aim:  We report a series of three successive patients with perianal rhabdomyosarcoma (RMS) managed with combined chemotherapy, radical surgery and radiotherapy

Methods: Ethical consent was obtained. We reviewed the hospital records of three patients with perianal rhabdomyosarcoma who were treated successively from 2014 to 2017.  Tumor presentation, treatment and survival are described.

Results: Two girls aged 15 and 16 (patient 1 and 2) and one boy aged five (patient 3) were referred because of a suspected perianal abscess. In patients 1 and 2 clinical and radiologic examination disclosed large perianal tumors inconsistent with abscess. Before definitive radiological imaging patient 3 had antibiotics and underwent a negative incision of the mass. Biopsies were performed 11–31 days after referral. Histology was RMS of alveolar (patients 1 and 2), and embryonal (patient 3) types.  Tumors originated from levator ani muscles, were 9–14cm in diameter, surrounded partially the anal sphincters and in patients 1 and 2 reached the posterior wall of vagina. Patient 1 had lymph node and bone metastases, patient 2 lymph node metastases and patient 3 no metastases. Pretreatment staging, IRS Clinical Group and Risk Groups were: patient 1 (stage 4, II, high), patient 2 (stage 3, GII, intermediate) and patient 3 (stage 3, I, low). All patients had colostomy and neoadjuvant chemotherapy (CWS-RMS 2009 program). In all three patients tumor response to neoadjuvant chemotherapy was poor and anus saving surgery was abandoned for abdominoperineal excision. Lymph nodes and margins were negative in removed specimens. After adjuvant chemotherapy and local radiation the patients were tumor free after 48, 13 and 18 months. Complications included pulmonary embolism (patient 1) and wound dehiscence and adhesion obstruction (patient 2).

Conclusion: In perianal RMS local surgical control required abdominoperineal excision. Confusion between perianal RMS and abscess may cause unnecessary delay in management.