Desmoplastic Small Round Cell Tumor of the Mandible in a Child With Unusual Plantar Metastasis Serhan Ku ¨peli, MD, MSc,* Kudret C ¸ag ˘lar, MD,w Dilek Birgen, MD,w Arzu Sungur, MD,z and Ali Varan, MD* Summary: Desmoplastic small round-cell tumor (DSRCT) is a rare and aggressive tumor that usually affects young males. Abdominal or pelvic disease is generally present in patients with DSRCT. Despite multimodality treatment, it still remains highly aggres- sive and has poor prognosis. We report a 16-year-old male with DSRCT in the mandible, an unusual site of the disease, treated with chemo-radiotherapy but recurred in an unexpected site 5 months after the completion of treatment. Key Words: desmoplastic small round cell tumor, mandible, recurrence, foot, treatment (J Pediatr Hematol Oncol 2010;32:e155–e157) D esmoplastic small round-cell tumor (DSRCT), which was first described as a specific disease by Gerald and Rosai in 1989, is a very rare and highly aggressive malignancy, occurring mostly in young males. 1,2 Despite multimodality treatment, the prognosis of the patients with DSRCT is extremely poor and there is no general agreement for the treatment of this malign disease. 3–5 The abdomen and pelvis are frequently reported in the literature as primary localizations. 2–5 Patients with DSRCT rarely present with single or multiple masses originating from the paratesticular region, pleura, posterior cranial fossa, soft tissues and bone, ovaries, kidney, and sinonasal localiza- tion. 1–10 A specific translocation, t(11;22)(p13;q12), is iden- tified in almost all cases. 1–10 Here, we report a case with DSRCT localized in an unusual site, the mandible, which initially responded well to treatment, but recurred in an unexpected site in a short period of time after the completion of treatment. CASE REPORT A 16-year-old male was admitted with the complaint of a tough swelling on the left side of his face in July 2006. The patient’s history was unremarkable and physical examination was otherwise normal. An MRI showed a contrasting mass around the left ramus of the mandible, extending from the edge of the mandible to the midline (Fig. 1). Histopathologic examination of the specimen taken by an incisional biopsy revealed well circumscribed solid tumor nodules and in some areas singly arranged tumor cells within a dense desmoplastic stroma. Tumor cells showed hyperchromatic nuclei with increased nuclear/cytoplasmic ratio, usually inconspicuous nucleoli, and frequent nuclear molding. The cytoplasm of the tumor cells was scant to moderate, pale blue with high mitotic activity. Immunohistochemistry revealed trilinear coexpression FIGURE 1. MR images showing contrasting mass extending from the edge of the mandible to the midline. Copyright r 2010 by Lippincott Williams & Wilkins Received for publication October 20, 2009; accepted January 22, 2010. From the *Departments of Pediatric Oncology, Institute of Oncology; zPathology, Hacettepe University Faculty of Medicine, Sıhhiye/ Ankara; and wPediatric Oncology Unit, Department of Pediatrics, Dr Burhan Nalbantog˘lu State Hospital, Nicosia, North Cyprus, Mersin, Turkey. Reprints: Serhan Ku¨peli, MD, MSc, Department of Pediatric Oncology, Institute of Oncology, Hacettepe University, 06100, Ankara-Turkey (e-mail: serkupeli@yahoo.com). CLINICAL AND LABORATORY OBSERVATIONS J Pediatr Hematol Oncol  Volume 32, Number 4, May 2010 www.jpho-online.com | e155