中華放射醫誌 Chin J Radiol 2004; 29: 99-103 99

Desmoplastic small round cell tumor is a raremalignant small cell neoplasm which tends to occurin adolescents and young adults. This tumor usuallypresents as an abdominopelvic mass with intraperi-toneal and hepatic metastasis. We report a case pre-senting as abdominal masses with unilateral pleuralseeding.

A 15-year-old woman without previous history ofmajor diseases came to our hospital because ofshortness of breath for 2 weeks. Chest X-rayrevealed massive amount of left pleural effusion. CTand MRI suggested two intraabdominal masses withmultiple left pleural seeding and massive left pleuraleffusion. The definitive diagnosis was made with theaid of echo-guided fine needle biopsy.

Key words: CT; Desmoplastic small round celltumor; Magnetic resonance imaging

Desmoplastic small round cell tumor is an aggres-sive malignant small round cell neoplasm that mainlyaffected adolescents and young adults. It usuallypresents as abdominal discomfort with abdominal mass[1]. The purpose of this paper is to describe a rare caseof desmoplastic small round cell tumor presenting asshortness of breath with massive left pleural effusionon CT & MRI.

CASE REPORT

A 15-year-old girl was quite well until two weeksago. She was sent to a local hospital due to shortnessof breath. Fever was also noted. Massive left pleuraleffusion was found. A pig-tail catheterization foreffusion drainage was undertaken at that time. She wasthen transferred to our hospital for further treatment.Physical examination at emergency department showeddiminution of breath sound at left lower lung field. Thecytologic findings in pleural effusion revealed manylarge pleomorphic hyperchromatic cell with prominentnucleus and small lymphocytes.

Plain chest radiographs showed massive leftpleural effusion without shifting of mediastinum.Trachea was at the midline (Fig. 1).

Chest CT showed nodular thickening of leftpleural surface with massive left pleural effusion(Fig.2a). Abdomen CT revealed two heterogeneousmasses over left upper abdomen (Fig.2b). No definitecalcification of the masses was found. Neitherabdominal lymphadenopathy nor hepatic metastasiswas noted. Chest and abdomen MR imagings revealedtwo masses over left upper abdomen. They were inho-mogeneous low signal intensity on T2*weighted image(SPGR), intermediate signal intensity on T1-weightedimage, heterogeneous contrast enhancement on Gd-T1-weighted image. Circumferential nodular thickening ofleft pleura with massive left pleural effusion wasrevealed (Fig.3a, 3b, 3c, 3d).

Reprint requests to: Dr. Chin-Ming JengDepartment of Radiology, Cathay General Hospital.No. 280, Sec. 4, Jen Ai Road, Taipei 106, Taiwan, R.O.C.

Intra-abdominal Desmoplastic Small RoundCell Tumor: CT and MR Findings: a casereportWEN-YU LEE

1 CHIN-MING JENG1 CHIH-YU HSU

2 YUNG-CHUAN SUNG2 SHIH-HUNG HUANG

3

YOUNG-CHEN WANG1 CHIN-HUE KUNG

1 CHAN-YING WU1

Department of Radiology1, Internal Medicine2, Pathology3, Cathay General Hospital

The definite diagnosis was made by echo-guidedfine needle biopsy from the left infradiaphragmaticarea. Histological examination showed desmoplasticround cell tumor (Fig.4). No pleural biopsy was done.According to histological findings, the pleural lesionwas regarded as metastasis.

The patient received chemotherapy. She isregularly followed up at OPD. After therapy for 6months, her general condition is stable.

DISCUSSION

Desmoplastic small round cell tumor is a rare,aggressive neoplasm that tends to affect adolescentsand young adults. It is characterized by a reciprocaltranslocation t(11;22)(p13;q12) associated with theEWS-WT1 (Ewing sarcoma-Wilms tumor 1) genefusion transcript [2]. It has a male predominance inprevious reports [3]. But a nearly equal sex ratio isreported by Pickhardt et al [4]. The manifestations ofdesmoplastic small round cell tumor are related to itslocation. The presentations of intra-abdominal desmo-plastic small round cell tumor are usually non-specificsuch as abdominal or pelvic symptoms and palpablemasses. The typical histological findings of desmo-plastic small round cell tumor is variable-sizedclusters of small, round or spindled cells lying in adesmoplastic stroma [2].

The characteristic CT presentation of desmo-plastic small round cell tumor is single or multipleperitoneal masses without any original organ that arelocated within the omentum or the mesentery, oradjacent to the bladder [4]. Tumors are often inho-

mogenous on CT due to focal hemorrhage or necrosis.Lymphadenopathy, punctate calcification of tumor,diffuse peritoneal thickening, hydronephrosis andhepatic metastasis are less common findings [3,4,5,6].Pleural dissemination is accompanied by diseasespreading in one study [3]. In our case, two intraperi-toneal masses without other intraperitoneal manifesta-tion were found. Obvious pleural rind with massivepleural effusion was noted.

Characteristics MRI findings of desmoplasticsmall round cell tumor are intermediate signalintensity on T1-weighted images, high signal intensity

Intraabdominal desmoplastic small round cell tumor100

Figure 1. CXR shows massive left pleural effusionwithout shifting of the mediastinum. The trachea was atthe midline.

Figure 2. a. Contrast-enhancing CT at the level of hepatic dome shows nodular thickening (white arrowheads) of leftpleura with massive left pleural effusion, a pig-tail catheter in place. b. Contrast-enhancing CT at the level of celiactrunk shows two heterogeneous masses (black arrows) over left upper abdomen.

2a 2b

on T2-weighted, inhomogeneous contrast enhance-ment on gadolinium-enhanced T1-weighted images[3,7]. MRI can well depict tumor location andextension by multiplanar images than other modalities.

Because no specific features of intra-abdominaldesmoplastic small round cell tumor. It must be differ-entiated with multiple peritoneal masses withoutobvious original organ. The differential diagnosisincludes malignant mesothelioma of peritoneum, non-Hodgkin’s lymphoma, malignant gastrointestinalstroma tumor, pseudomyxoma peritonei, peritonealmetastasis, tuberculosis. The malignant mesotheliomaof peritoneum seems to present as small modules

lining the surface of parietal peritoneum with adominant mass in one part of abdomen. The non-Hodgkin’s lymphoma usually mimics carcinomatosiswith mesenteric and retroperitoneal lymphadenopathy.The pseudomyxoma peritonei is low-attenuationmasses with scalloping parenchymal organ margins onCT. The peritoneal metastasis comes from ovarian andgastrointestinal primaries with masses and soft tissueinfiltration and ascites. The tuberculosis may showlow attenuation lymphadenopathy, exudative ascites,mesenteric masses on CT.

The treatment of desmoplastic small cell isdifficult including chemotherapy, radiotherapy,

Intraabdominal desmoplastic small round cell tumor 101

Figure 3. a. Axial T1-weighted image (TR/TE = 1445/40.5ms, FSE-XL/90) shows two intermediate signal intensitymasses (black arrows) over left upper abdomen. b. Axial Gd-T1-weighted image (TR/TE=7.8/4.3ms, FSPGR/20) showstwo heterogeneous contrast enhancing masses (black arrows) over left upper abdomen. c. Axial T1-weighted contrast-enhancing image shows inhomogeneous contrast enhancement of the nodular thickening of pleura (black arrows) of leftlower pleural space. d. Coronal T1-weighted contrast-enhancing image shows heterogeneous contrast enhancement ofthe left upper abdominal masses (black arrow), nodular thickening of left pleura (white arrows) with left pleuraleffusion.

3c 3d

3a 3b

surgical resection. Outcome of the majority of casesare poor despite of aggressive therapy. The patientsusually die within the first 2 years after diagnosis.However, recent studies of combined modalityprotocol associated with autologous peripheral bloodstem cell transplantation have been tried [8] . ◆

REFERENCE

1. Gerald WL, Miller HK, Battifora H, et al. Intra-abdomi-nal desmoplastic small round-cell tumor: report of 19cases of a distinctive types of high-grade polyphenotyp-ic malignancy affecting young individuals. Am J SurgPathol 1991; 15: 499-513

2. Lae ME, Roche PC, Jin L, et al. Desmoplastic smallround cell tumor: a clinicopathologic, immunohisto-chemical, and molecular study pf 32 tumors. Am J SurgPathol 2002; 26: 829-835

3. Tateishi U, Hasegawa T, Kusmoto M, et al.Desmoplastic small round cell tumor: imaging findingsassociated with clinicopathologic features. J ComputAssist Tomogra 2002; 26: 579-583

4. Pickhardt PJ, Fisher AJ, Balfe DM, et al. Desmoplasticsmall round cell tumor of the abdomen: radiologic-histopathologic correlation. Radiology 1999; 210: 633-638

5. Varma DG, McDaniel K, Ordonez NG, et al. Primarymalignant small round cell tumor of the the abdomen:CT findings in five cases. AJR 992; 158: 1031-1034

6. Wang HK, Chen JD, Tiu CM, et al. Intra-abdominaldesmoplastic small cell tumor: CT and ultrasoundimages. Clin J Radiol 1999; 24: 215-219

7. Outerwater E, Schiebler ML, Brooks JJ. Intraabdominaldesmoplastic small round cell tumor: CT and MR find-ings. J Comput Assist Tomogr 1992; 6: 9-32

8. Kurre P, Felgenhauer JL, Miser JS, et al. Successfuldose-intensive treatment of desmoplastic small roundcell tumor in three children. J Pediatr Hematol oncol2000; 2: 446-450

Intraabdominal desmoplastic small round cell tumor102

Figure 4. Photomicrography of the specimen shows thetumor composed of cohesive epithelial-like nests andtrabeculae of small to medium-sized, roundhyperchromatic cells, with surrounding desmoplasticstroma (Hematoxylin and eosin stain, x 200).

Intraabdominal desmoplastic small round cell tumor 103

腹腔內促纖維性小細胞瘤：電腦斷層及磁振影像之病例報告

李紋瑜1 鄭慶明1 徐志育2 宋詠娟2 黃世鴻3 王永成1 孔慶惠1 吳昭瑩1

國泰綜合醫院　放射線科1 內科2 病理科3

促纖維性小細胞瘤是一種十分罕見的惡性腫瘤，好發於青少年及年輕人。通常以腹部骨盆

腫瘤併腹膜及肝轉移表現。我們要報告一例以腹部腫瘤表現併單側肋膜轉移。

一位15歲之女性，以前沒有疾病史，由於兩週呼吸急促來本院就診。胸部X光片發現大量

左側肋膜積水，電腦斷層及磁振影像發現腹腔內腫瘤合併多處左側肋膜轉移及大量肋膜積水。

確定診斷是靠超音波下細針切片。

關鍵詞：電腦斷層；促纖維性小細胞瘤；磁振影像