Journal of the New Zealand Medical Association, 04-July-2008, Vol 121 No 1277
Castleman’s disease is a rare lymphoproliferative disorder characterised by masses of lymphoid tissue. The most common site of the disease is the mediastinum.
We report the rare case of a 36-year-old Chinese man with a Castleman’s tumour in the retroperitoneal cavity located below the level of the right kidney—and mimicking a sarcoma, neural tumour, metastasis, or lymphoma.
A 36-year-old man presented with a self-detected mass in the right lower abdominal quadrant. He had no medical history or past surgical history. Physical examinations were generally normal, except for the palpable mass over the right lower quadrant of the abdomen. The results of a routine complete blood count and his serum biological profile were unremarkable.
A heterogeneously enhanced lesion with multiple low-attenuation areas was present on post-contrast computed tomography (CT; Figure 1). The mass was in the right retroperitoneal cavity, adjacent to the right psoas muscle. The fat plane between the retroperitoneal mass, right psoas muscle, common iliac vessels, and right ureter was clear. The encapsulated mass was completely removed.
Figure 1. Axial post-contrast CT scan shows a heterogeneously enhanced right retroperitoneal mass with multiple low-attenuation areas (black arrow)
Its gross pathology revealed an encapsulated tumour measuring about 8 cm, located in the right retroperitoneal cavity, grey in colour, with an ovoid-shaped contour and with haemorrhage. Microscopically, the specimen showed the proliferation of numerous lymphoid follicles with collagenous germinal centres and hyaline vascular proliferation, the appearance typical of hyaline vascular-type Castleman’s disease. There were no surgical complications and the patient recovered well.
A CT scan after 3 months was normal, with no evidence of recurrence.
Castleman’s disease is a poorly understood proliferative disease of the lymphoid tissue that occurs mainly in young, healthy patients in the age range of 8–66 years, with no sex predominance.1 Most (70%) Castleman’s disease occurs in the mediastinum, with 20% in the neck, shoulder, and inguinal regions, and 7% in the retroperitoneum.2
Castleman’s disease is classified into two pathological subtypes: a localised and a multicentric subtype.3 Localised Castleman’s disease presents as a solitary mass, which may be well circumscribed and usually has a benign course. In contrast, multicentric Castleman’s disease usually has a worse clinical course, which can include malignancy, infection, and death.4
Abdominal Castleman’s disease has been described in the radiology literature as an enhanced mass over the mesentery, retroperitoneum, porta hepatis, and pancreas.5 Meador and McLarney reported that an enhanced pattern on abdominal CT and a Castleman’s disease tumour of less than 5 cm usually presents with homogeneous enhancement, whereas tumours greater than 5 cm usually present with heterogeneous enhancement with areas of low attenuation.5 These radiological features are not sufficiently specific to differentiate Castleman’s disease from retroperitoneal masses such as sarcoma, metastasis, lymphoma, or neural tumour.
To the best of our knowledge, retroperitoneal sarcoma is usually a large unilateral mass, displacing the retroperitoneal organs or viscera. It is usually heterogeneously enhanced on contrast-enhanced CT.
Retroperitoneal lymphoma tends to surround the adjacent vessels, presenting with a “floating” aorta5 and low attenuation, without significant enhancement on contrast-enhanced CT.6
Although radiological images can help us differentiate the possible diagnoses of a retroperitoneal mass, surgical resection and histological evaluation allow an absolute diagnosis of Castleman’s disease. The use of haematoxylin-eosin (H&E) staining for Castleman’s disease was important in this case and led to the correct diagnosis.
In conclusion, we have reported a large retroperitoneal mass (>5 cm) with a heterogeneously enhanced pattern and areas of low attenuation. Radiological imaging studies are not sufficiently specific to identify Castleman’s disease and a histopathological examination is necessary for a final diagnosis.
Author information: Chien-Ming Liao; Ying-Chun Chiu; Wei-Chou Chang; Chang-Hsien Liu; Ching-Jiunn Wu; Guo-Shu Huang; Radiologists; Department of Radiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China
Correspondence: Ching-Jiunn Wu, MD, Department of Radiology, Tri-service General Hospital, 325, Sec 2, Cheng-Kung Rd, Neihu 114, Taipei, Taiwan, Republic of China. Fax:+886 (0)2 87927245; email: firstname.lastname@example.org
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