submit.radiology.or.kr J Korean Soc Radiol 2011;65(4):395-398
395 INTRODUCTION
Schwannomas are encapsulated tumors arising from the neural sheath. Schwannomas arising in lymph nodes are very rare, with only less than 10 cases documented as true intra- nodal schwannomas (1-6). The masses are usually small in size, measuring less than 5 cm, a solid mass with a scarcity of internal necrosis or cystic component (1-6). We report a case of an approximately 10 cm ancient schwannoma arising in the retroperitoneal lymph node, which showed very similar imaging findings to a gastrointestinal stromal tumor (GIST).
CASE REPORT
A 66-year-old woman presented with abdominal pain with nausea and vomiting. A large firm mass was palpated in the left upper quadrant on physical examination. The woman had
been in good health, and a routine hematological examina- tion and biochemical tests were within normal limits. For tu- mor markers, carbohydrate antigen 19-9 (CA 19-9), carcino- embryonic antigen, and alpha fetoprotein were all negative.
Contrast-enhanced CT demonstrated a well-encapsulated large mass (about 10 cm maximum diameter) abutting the greater curvature of the gastric body in the gastrosplenic re- gion. The left adrenal gland was clearly demonstrated and the tumor showed heterogeneous intermediate to low attenuation with internal necrotic portions and dot-like capsular calcifica- tions (Fig. 1A, B). A small bowel series showed a large soft tis- sue mass abutting the greater curvature of the gastric body and indenting the proximal small bowel loops (Fig. 1C). With the CT findings and small bowel series, GIST was suggested to be the most likely result. Ultrasound (US)-guided percuta- neous needle biopsy was performed from a large lobulated mass with internal cystic change in the left upper abdomen
Case Report
pISSN 1738-2637
J Korean Soc Radiol 2011;65(4):395-398
Received April 20, 2011; Accepted August 4, 2011 Corresponding author: Sook Namkung, MD Department of Radiology, Hallym University College of Medicine, Chuncheon Sacred Heart Hospital, 153 Gyo-dong, Chuncheon 200-704, Korea.
Tel. 82-33-240-5156 Fax. 82-33-242-7085 E-mail: [email protected]
Copyrights © 2011 The Korean Society of Radiology
A 66-year-old-woman is presented with intranodal schwannoma of the retroperito- neum. Ultrasonography (US) and computed tomography (CT) results demonstrated a large encapsulated mass with internal cystic or necrotic portions in the gastrosplenic space. The tumor abutted the greater curvature of the gastric body and slightly in- dented the proximal small bowel loops on a small bowel series. The observations sug- gested a gastrointestinal stromal tumor. The mass was surgically proven to be a retro- peritoneal tumor and histopathologically intranodal ancient schwannoma.
Index terms Schwannoma Retroperitoneal Lymph Node CT
Ultrasonography
Intranodal Schwannoma Mimicking a Gastrointestinal Stromal Tumor of the Stomach: A Case Report
1위의 위장관 기질성 종양과 비슷한 소견의 임파절내 신경초종: 증례 보고1
Kyung Bum Nam, MD
1, Sook Namkung, MD
1, Heung Cheol Kim, MD
1, Hae Sung Kim, MD
2, Byoung Yoon Ryu, MD
2, Young Hee Choi, MD
3Departments of 1Radiology, 2General Surgery, 3Pathology, Hallym University College of Medicine, Chuncheon Sacred Heart Hospital, Chuncheon, Korea
Intranodal Schwannoma Mimicking a Gastrointestinal Stromal Tumor of the Stomach
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J Korean Soc Radiol 2011;65(4):395-398
396
cell tumors such as spindle-cell carcinoma, melanoma, Kapo- si’s sarcoma, spindle-cell follicular dendritic cell sarcoma, in- terdigitating dendritic cell sarcoma, and schwannomas, might be considered. Immunohistochemical staining showed posi- tive reactivity for vimentin and S-100 (Fig. 1F). Finally, an- cient and giant schwannomas arising in a lymph node were confirmed.
DISCUSSION
Schwannomas commonly arise along the peripheral nerves as well as in the cranial nerve and dorsal spinal nerve roots.
Abdominal schwannomas usually have a maximum diame- (Fig. 1D). Histopathologically a malignancy was suggested. At
surgery, a large retroperitoneal tumor with a lobulated surface was palpated, and tumor extirpation with splenectomy was performed. The gross specimen of the tumor was 10 × 8 cm in size, and its surface was encapsulated. The cut surface of the mass showed a yellowish white mucoid solid pattern with cystic changes. Microscopically, the subcapsular area of the mass showed a very narrow rim of lymphoid tissue, suggest- ing the residual lymph node tissue (Fig. 1E). Most of the mass consisted of spindle cell proliferation with a whorl-like pat- tern. In addition, multifocal cystic degeneration, foamy mac- rophages, scattered lymphoid cell infiltration, and atypical nuclei were present. With these findings, metastatic spindle-
D A
E F
B C
Fig. 1. Intranodal schwannoma of the retroperitoneum in a 66-year-old woman.
A, B. Contrast-enhanced (A) axial and (B) coronal CT images demonstrate a well encapsulated large mass with internal cystic portions (short ar- rows) and wall calcifications (long arrows) in the gastrosplenic region abutting the greater curvature of the gastric body. The left adrenal gland is clearly visualized (white arrow).
C. A small bowel series shows a large soft tissue mass shadow abutting the greater curvature of the gastric body (thin arrows) and indenting the proximal small bowel loops (thick arrows).
D. Longitudinal ultrasonogram shows a large mass (arrows) with internal cystic changes (asterisk) in the left upper abdomen.
E. Low power photomicrograph demonstrates three layers composed of outer fibrous capsule (asterisk), middle thin lymphoid tissue of the lymph node, and the lowest layer of the spindle cell neoplastic lesion (arrow) (Hematoxylin-Eosin; × 40).
F. High power photomicrograph demonstrates the positive immunoreactivity of S-100 protein in spindle cells (Immunohistochemical staining; × 100).
Kyung Bum Nam, et al
submit.radiology.or.kr J Korean Soc Radiol 2011;65(4):395-398
397
The mass was found to be a retroperioneal tumor at sur- gery, and the final histopathological diagnosis was an ancient intranodal schwannoma with immunohistochemical staining and positive reactivity for S-100.
A retrospective review of the CT images of our case indicat- ed that the findings of a well-defined large mass with internal cystic or necrotic change and wall calcifications are comparable to the imaging findings of a rare giant ancient schwannoma in the retroperitoneum (7).
Intranodal schwannomas are clinically nonspecific, and in- cidentally identified as small tumors on CT scan, and are cur- able by the simple extirpation of the tumor with no eventful clinical outcome.
In conclusion, we report a case of a large retroperitoneal in- tranodal schwannoma mimicking a GIST with illustration of the imaging findings.
REFERENCES
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2. Piana S, Gelli MC, Cavazza A, Serra L, Gardini G. Ancient schwannoma arising in a lymph node: report of a case and review of the literature. Pathol Res Pract 2002;198:51-54 3. Reinus C, Shutin O, Reissman P. Intranodal schwannoma
presenting as an adrenal mass. Histopathology 2004;45:
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4. Grant DG, Breitenfeldt N, Shepherd NA, Thomas DM. In- tranodal neurilemmoma presenting as parotid mass. J Lar- yngol Otol 2009;123:912-914
5. Black JO, Zhai QJ, Varona OB, Ordonez NG, Luna MA. Pri- mary schwannoma in a cervical lymph node. Head Neck 2010;32:964-969
6. Jung JH, Yoo J, Kang SJ, Lee KY. Schwannoma arising in a lymph node: a brief case report. Korean J Pathol 2009;43:
271-273
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8. Weiss SW, Gnepp DR, Bratthauer GL. Palisaded myofibro- blastoma. A benign mesenchymal tumor of lymph node.
terless than 5 cm and appear as a well- demarcated round or oval mass that frequently demonstrates prominent cystic de- generation and punctate, mottled, or curvilinear calcification on CT scans. Retroperitoneal schwannomas may be larger tu- mors that had been growing slowly over a long period of time.
Inadequate blood supply to the center of the tumor sometimes causes secondary degenerative changes such as cyst malforma- tion, calcification, hemorrhage, and hyalinization. Theses de- generative tumors are called ancient schwannomas (7).
Schwannomas arising in the lymph nodes are very rare.
Some cases previously diagnosed as intranodal schwannomas have been reclassified as palisaded myofibroblastomas on the basis of some peculiar histological or immunohistochemical features (8). Although benign, it is important to distinguish schwannomas from metastatic spindle cell carcinomas, mela- nomas and sarcomas histopathologically (9).
We have found only six cases of true intranodal schwanno- mas reported in the literature, one in the subcutaneous lymph node over the posterior surface of the left scapula, one in the cervical lymph node, one in the parotid gland, one in the pericolic lymph node, and two in the retroperitoneal lymph nodes. They all had maximum diameters less than 5 cm, and showed relatively homogeneous density with no calcification or cystic change on CT scans. Moreover, they were all initially suggested to be benign tumors with a clinical history and im- aging findings, except for one case which had a colon cancer suggesting pericolic lymph node metastasis (1-6).
In our case, the tumor was quite large with a maximum di- ameter measuring approximately 10 cm and seen in the gas- trosplenic space. Therefore, it was difficult to determine the tumor location, whether intraperitoneal or retroperitoneal.
However, we suggested the intraperitoneal location because the tumor was clearly separated from the left adrenal gland.
In addition, the mass was well demarcated with an internal cystic or necrotic change with wall calcifications, and also abutted the gastric wall on CT scans. These imaging findings were very similar to large GISTs that have been illustrated in the literature (10).
We performed US-guided percutaneous needle biopsy, and obtained a histopathologic result suggesting malignancy. With imaging and pathologic findings, the preoperative diagnosis was suggested to be a malignant GIST most likely.
Intranodal Schwannoma Mimicking a Gastrointestinal Stromal Tumor of the Stomach
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ton DC: Armed Forces Institute of Pathology, 1995:435- 526
10. Lau S, Tam KF, Kam CK, Lui CY, Siu CW, Lam HS, et al. Im- aging of gastrointestinal stromal tumour (GIST). Clin Radi- ol 2004;59:487-498
Am J Surg Pathol 1989;13:341-346
9. Warnke RA, Weiss LM, Chan JKC, Cleary ML, Dorfman RF.
Nonhematolymphoid tumors and tumor-like lesions of lymph node and spleen. In: Tumors of the lymph nodes and spleen. Atlas of Tumor Pathology, 3rd series. Washing-
위의 위장관 기질성 종양과 비슷한 소견의 임파절내 신경초종:
증례 보고1
남경범
1· 남궁숙
1· 김흥철
1· 김해성
2· 류병윤
2· 최영희
366세 여자 환자에서 발생한 후복막강 임파절내 신경초종의 증례를 보고하고자 한다. 초음파와 CT에서는 위와 비장 사 이에 위치하고 피막에 싸여있으며 내부에 낭종 혹은 괴사 소견을 동반한 경계가 좋은 커다란 연부조직 종괴로 보였다. 소 장조영술에서는 종괴에 의해 위체부의 대만곡이 밀리고 위점막 주름이 일부 펴져 있었으며 공장의 근위부를 약간 밀고 있 는 소견을 보여 영상학적으로 위체부에서 발생한 위장관 기질성 종양으로 진단하였다. 개복술을 통해 후복막강 종괴로 확인되었고 조직학적으로 임파절내 신경초종으로 확진되었다.
한림대학교 의과대학 춘천성심병원 1영상의학과학교실, 2외과학교실, 3해부병리과학교실
