The mesenteric form of Castleman disease is a localized or multicentric lymphoproliferative disorder occurring in the mesentery. The unicentric (hyaline-vascular) type is most common and typically presents as a well-defined, intensely enhancing hypervascular mesenteric mass. The multicentric type, known as the plasma cell variant, is strongly associated with HHV-8 and HIV infection, characterized by systemic symptoms, widespread lymphadenopathy, and poor prognosis. The mesentery, retroperitoneum, and abdomen are the most common extrathoracic sites of involvement. While unicentric disease can be cured by surgical resection, multicentric disease requires systemic therapy. Biopsy is the gold standard for diagnosis; imaging findings can strongly support the diagnosis but pathological confirmation is mandatory.
Age Range
20-55
Peak Age
35
Gender
Equal
Prevalence
Rare
The pathogenesis of Castleman disease varies by subtype. In the unicentric hyaline-vascular type, abnormal follicular dendritic cells excessively secrete angiogenic cytokines such as IL-6 and VEGF, leading to intense capillary proliferation and characteristic 'onion skin' pattern of concentric mantle zone hyperplasia. This intense vascularity forms the basis of the prominent hypervascular enhancement on CT and MRI — homogeneous intense arterial phase enhancement reflects the tumor's rich capillary network. In the multicentric type, HHV-8 infection triggers systemic inflammation through viral IL-6 production, causing plasma cell infiltration. In mesenteric localization, a 'feeding vessel' sign is frequently seen around the mass, and tumor blush pattern is observed on angiography. The intermediate-to-high signal intensity on T2-weighted MRI reflects free water protons in the vascular stroma and loose connective tissue. Calcification, particularly in the hyaline-vascular type, can be seen in central or peripheral patterns and occurs through dystrophic calcification mechanisms.
The combination of an intensely homogeneously enhancing hypervascular mass in the mesentery in arterial phase with a feeding vessel entering the mass is highly characteristic of the hyaline-vascular type of Castleman disease. This combination reflects the tumor's VEGF-mediated intense neovascularity and its supply from a single dominant feeding artery.
Prominent homogeneous intense enhancement in arterial phase, significantly more enhancing than surrounding mesenteric structures. Enhancement degree frequently approaches that of the aorta and major arteries. In the unicentric hyaline-vascular type, enhancement is homogeneous and uniform; in larger masses (>5 cm), heterogeneity may develop with peripheral cystic/necrotic areas. A 'feeding vessel' sign — a prominent artery or vein entering the mass — is frequently seen and supports the diagnosis.
Report Sentence
Well-defined hypervascular mesenteric mass with prominent homogeneous intense arterial phase enhancement and accompanying feeding vessel sign is observed, suggesting Castleman disease (hyaline-vascular type) as the leading diagnosis.
Enhancement persists in the portal venous phase but shows mild decrease compared to the arterial phase (persistent enhancement pattern). Mass density remains significantly higher than surrounding mesenteric fat and soft tissue. This persistent enhancement pattern reflects the retention of contrast by the dense vascular stroma of the mass. In the multicentric type, more heterogeneous portal venous enhancement and accompanying lymphadenopathy may be seen.
Report Sentence
The mass demonstrates persistent enhancement in the portal venous phase, consistent with dense vascular stroma.
Central, punctate, or branching calcifications may be observed within the mass on non-contrast CT. Calcification incidence is reported at 10-30% in the hyaline-vascular type. Calcifications are usually centrally located and may sometimes show a 'stellate pattern' or arborizing (branching) pattern. The mass demonstrates higher density than surrounding mesenteric fat (40-60 HU) on non-contrast phase.
Report Sentence
Central branching calcifications within the mesenteric mass are consistent with the hyaline-vascular type of Castleman disease.
The mass demonstrates homogeneous intermediate-to-high signal intensity on T2-weighted sequences. Signal intensity is typically higher than muscle but lower than fluid signal. Flow void areas (vascular signal voids) can be seen within or at the periphery of the mass, reflecting intense vascularity.
Report Sentence
The mesenteric mass demonstrates homogeneous intermediate-to-high signal intensity on T2-weighted sequences with flow void areas within the mass.
Dynamic contrast-enhanced MRI demonstrates prominent homogeneous gadolinium enhancement in the arterial phase. Enhancement pattern parallels that on CT — intense, early, homogeneous. Enhancement persists in delayed phases (persistent pattern). On DWI, the mass typically shows mild-to-moderate diffusion restriction; ADC values are relatively higher compared to malignant masses.
Report Sentence
On MRI, the mesenteric mass demonstrates prominent homogeneous gadolinium enhancement in the arterial phase with persistent enhancement pattern in delayed phases.
Color and power Doppler US demonstrate prominent hypervascular flow pattern within the mass. Both central and peripheral vascularization are present. Feeding artery is frequently visualized. Spectral Doppler typically shows low-resistance arterial flow (RI <0.5), reflecting the rich capillary bed.
Report Sentence
Doppler US demonstrates prominent hypervascular flow pattern and feeding artery within the mass.
Criteria
Localized mass in a single anatomic region, prominent hypervascular enhancement, concentric mantle zone hyperplasia and hyalinized capillary proliferation on histology. Usually presents as asymptomatic or with local compression symptoms.
Distinct Features
Most common type (70-90%), young adults (20-40 years), good prognosis, surgical resection is curative. Homogeneous intense enhancement, central calcification may be present. Feeding vessel sign frequently seen. Recurrence rare.
Criteria
Lymphadenopathy in multiple anatomic regions, systemic symptoms (fever, night sweats, weight loss), hepatosplenomegaly, interfollicular plasma cell infiltration on histology.
Distinct Features
Strong association with HHV-8 and HIV, poor prognosis, requires systemic therapy. Heterogeneous enhancement, widespread lymphadenopathy, hepatosplenomegaly. Increased lymphoma risk.
Criteria
Multicentric disease + HHV-8 positivity confirmed by IHC or PCR. HIV coinfection frequently present. Increased risk of Kaposi sarcoma and primary effusion lymphoma.
Distinct Features
Most aggressive form, Kaposi sarcoma coincidence 40-75%, high lymphoma transformation risk. Prominent splenomegaly. Treatment: antiretroviral + rituximab/etoposide.
Criteria
Multicentric disease + HHV-8 negative. Fits TAFRO syndrome or iMCD-NOS subtypes. IL-6 pathway plays central role in pathogenesis.
Distinct Features
Anti-IL-6 therapy (siltuximab/tocilizumab) first-line. High organ failure risk in TAFRO subtype. Heterogeneous lymphadenopathy, effusions, hepatosplenomegaly typical.
Distinguishing Feature
Non-Hodgkin lymphoma typically shows more heterogeneous enhancement, presents with multiple lymphadenopathy, and does not demonstrate a prominent feeding vessel sign. Castleman's homogeneous intense enhancement and solitary mass pattern distinguish it from lymphoma.
Distinguishing Feature
Mesenteric desmoid tumor shows variable T2 signal (low signal areas due to collagen content), progressive enhancement pattern, and is hypovascular. Castleman's intense arterial enhancement and hypervascular nature markedly differ from desmoid.
Distinguishing Feature
Mesenteric carcinoid tumor frequently presents as a calcified 'spoke-wheel' pattern mass showing desmoplastic reaction and retraction. Castleman lacks desmoplastic reaction; enhancement is more homogeneous and intense.
Distinguishing Feature
Extraintestinal GIST typically shows heterogeneous enhancement, contains central necrosis/hemorrhage, and has more irregular margins. Castleman's homogeneous intense enhancement, well-defined structure, and calcification distinguish it from GIST.
Urgency
routineManagement
surgicalBiopsy
NeededFollow-up
specialist-referralSurgical resection is curative for the unicentric hyaline-vascular type, with recurrence after complete resection being very rare (less than 5%). Preoperative embolization may be considered due to intense vascularity. In the multicentric type, treatment depends on subtype and HHV-8 status: siltuximab (anti-IL-6) for iMCD, rituximab + antiretroviral therapy for HHV-8-positive type. Diagnosis requires histopathological confirmation; imaging findings are suggestive but insufficient for definitive diagnosis.
Hyaline-vascular type Castleman disease is curable with surgical excision. Multicentric type shows systemic symptoms and has worse prognosis. Biopsy is needed for diagnosis. Risk of lymphoma transformation exists.