Pelvic Castleman's disease presenting as an abdominal mass in a man

Clinical History

A 45-year-old man complained of an abdominal mass for one year. By specialized examination we found the mass had poorly mobility. He had no history of injury, previous surgery or any relevant family history.

Imaging Findings

Abdominal ultrasound revealed mixed echo lumps in the right part of the pelvis, short clavite colour blood flow signal in the internal and blood signal. Upper and lower gastro-intestinal endoscopic studies confirmed the presence of no ulcerated gastric lesion (caecum, transverse and sigmoid colon). Abdomino-pelvic contrast-enhanced CT showed an iso-dense mass of about 11 cm in diameter in the pelvic cavity, the centre of which was punctate calcification and multiple patchy necrosis areas. At arterial phase, the tumour showed a non-homogeneous hypodense mass including variously enhanced scattered patches. At portal phases, the degree and extent of enhancement of the tumour gradually increased. No enlarged lymph nodes were present.
MRI detected a well-defined solid mass with T1-hypointense and T2-hyperintense and restricted diffusion.
Laparoscopic mass excision was performed and pathological diagnosis of Hyaline-vascular Castleman’s disease was made.

Discussion

Castleman's disease is a peculiar type of benign lymph node hyperplasia, first described by Benjamin Castleman in 1956 [1] .The disease can arise in any lymphoid tissue in the body, usually occurs in the mediastinum and it is seldom found in neck, pancreas or pelvis. Several factors have been proposed to be associated with the development of CD, which include chronic low-grade inflammation, an immunodeficient state, and autoimmunity [2]. Clinically, the disease in terms of intumescent lymph node distribution is divided into focal and more centred. Pathologically, according to the histologic features it can be divided into clear vascular (HV) type, plasma cells (PC) type and hybrid type with the characteristics of both. The localized form, usually paucisymptomatic, is the hyaline vascular (HV) type, characterized by a solitary enlarged lymph node. CD must be included into the differential diagnosis of lymphadenopathies. Unicentric hyaline vascular Castleman’s disease is often curable with surgery; treatment of multicentric Castleman’s disease may require steroid therapy, chemotherapy, antiviral medication, or the use of antiproliferative regimens. When specific treatment is performed, the prognosis of HVV and local PCV is favourable: the disease is surgically cured in 95% of cases [3].
On imaging, Castleman’s disease in the pelvic cavity is rare [4]. Almost all tumours have clear margins and show obvious enhancement on CT. Approximately 10% of the lesions have internal calcifications, which are characteristically coarse or demonstrate a distinctive branching pattern [5]. At magnetic resonance (MR) imaging, the lesions of hyaline vascular Castleman’s disease classically exhibit heterogeneous T1 and T2 hyperintensity compared with skeletal muscle. Prominent flow voids may be seen, which identify the feeding vessels. Hyaline vascular CD can manifest as a mesenteric or retroperitoneal mass with mild contrast enhancement, with an imaging appearance mimicking retroperitoneal adenopathy and carcinoid tumour. When it occurs in the presacral region, it must be differentiated from a nerve sheath tumour, inflammatory pseudotumour, desmoid tumour or lymphoma. Unlike malignant fibrous histiocytoma (MFH), it is a rare tumour that mostly involves adults aged 50 to 70, and the most common anatomic location is the lower extremities [6]. T2WI manifestation of MFH depends on the ratio of its internal myxoid matrix and collagen fibres, and the solid part of the mass had moderate or more uneven enforcement, which is not similar to CD. This case should be differentiated from fibrosarcoma, as sometimes fibrosarcoma has punctate calcifications on CT too, but adjacent bone erosion.

Differential Diagnosis List

Final Diagnosis

Castleman’s disease

URL:	https://www.eurorad.org/case/13977
DOI:	10.1594/EURORAD/CASE.13977
ISSN:	1563-4086