Castle in Pelvis

Clinical presentation
30yr old female presented for routine third trimester antenatal scan at 37 weeks of gestation. An incidental 5X4cm sized left lower quadrant solid mass was detected in the maternal abdomen. With the differential diagnoses of solid ovarian/paraovarian mass a follow up USG was done in the post natal period, which showed increase in size of the lesion.
Subsequently she underwent MRI and it showed heterogeneously enhancing retroperitoneal mass lesion of size 7.5X5x5cm in left lower quadrant interposed between left common iliac artery and left psoas muscle. Lesion caused anteromedial displacement of distal segment of common iliac artery and splaying of internal / external iliac arteries. It was appearing iso to mildly hyperintense on T1WI, T2WI with evidence of intralesional flow voids and areas of central restricted diffusion. Uterus & ovaries appeared normal. There were no concomitant intra-abdominal masses or organomegaly. No other significantly enlarged lymph nodes were detected. Based on the imaging features, differential diagnostic possibilities of lymph nodal mass/paraganglioma / hemangiopericytoma / solitary fibrous tumor were considered.

She underwent laparoscopic excision of the tumor and a 8X6x6cm sized lobulated mass was removed.
On histopathological examination, lymphnodal mass consistent with Castleman’s disease( hyaline vascular type ), was diagnosed.
{HPR – lymph node showing partially effaced architecture with preserved marginal sinuses. Scattered follicles showing onion skinning of the mantle zones and hyalinised atrophic germinal centres with predominance of follicular dendritic cells and “lolipop”shaped blood vessels were noted. The interfollicular areas are expandedand show hyalinised blood vessels. Foci ofdense hyaline fibrosis and calcification areseen.}
Discussion
Castleman disease otherwise known as angiofollicular or benign giant lymph node hyperplasia is an uncommon benign lymphoproliferative disorder. The first description about the constellation of pathological findings of the disease was by Dr. Benjamin Castleman in the 1950s (1).
Clinicoradiological subtypes include unicentric disease (UCD) and multicentric disease (MCD). Multicentric variant may be human herpes virus HHV- 8 associated or HHV-8 negative idiopathic (iMCD) form.
The histopathogenetic classification distinguishes hyaline vascular Castleman disease, plasma cell Castleman disease, human herpesvirus 8 (HHV-8)–associated Castleman disease, and multicentric Castleman disease not otherwise specified. (2)
Hyaline vascular Castleman disease represents 90% of the cases of Castleman disease. It is asymptomatic with a benign course and occurs most often in young adults, with a median age at diagnosis in the 3rd or 4th decade(3).HHV-8–associated Castleman disease is more aggressive, occurs predominantly in immunosuppressed / human immunodeficiency virus (HIV)–positive patients and manifests commonly with generalized lymphadenopathy, constitutional symptoms, and hematologic and/or immunologic abnormalities.(4)
Castleman disease occurs throughout the body. Of all cases of Castleman disease, approximately 70% occur in the chest, 15% in the neck, and 15% in the abdomen and pelvis, involving primarily lymphatic tissues. Extralymphatic sites of involvement include the lungs, larynx, parotid glands, pancreas, meninges, and muscles. (5)
Imaging features
Castleman disease is a great mimic.The classic CT appearance of hyaline vascular Castleman disease is that of a solitary enlarged lymph node or localized nodal masses that demonstrate homogeneous intense enhancement after contrast material administration. Three patterns of involvement have been described, including a solitary noninvasive mass, infiltrative mass with associated lymphadenopathy and matted lymphadenopathy without a dominant mass (6). Hyaline vascular Castleman disease can manifest as a mesenteric or retroperitoneal mass with mild contrast enhancement, with an imaging appearance mimicking retroperitoneal adenopathy and carcinoid tumor. Hyaline vascular Castleman disease has a considerable predilection for involvement of the thorax, where it typically manifests as an avidly enhancing mediastinal nodal mass. Mediastinal Castleman disease can mimic thymoma, lymphoma, sarcoma, hemangiopericytoma, neural crest derived neoplasms such as paraganglioma, neurofibroma, or schwannoma, and chest walltumors.Hilar Castleman disease may be confused with bronchial adenoma. Pleural Castleman disease is unusual and can manifest as a well-defined mass or with an associated pleural effusion. Pericardial Castleman disease can mimic a pericardial cyst.
Prominent feeding vessels in the close vicinity of a nodal mass are a clue to the diagnosis and are predominantly seen in hyaline vascular Castleman disease. Approximately 10% of the lesions have internal calcifications, which are characteristically coarse or demonstrate a distinctive branching pattern More commonly, nonspecific calcifications are observed. Central hypoattenuation in nodal masses is unusual but may be seen in few cases.
At magnetic resonance (MR) imaging, the lesions of hyaline vascular Castleman disease classically exhibit heterogeneous T1 and T2 hyperintensity compared with skeletal muscle Prominent flow voids may be seen, which identify the feeding vessels. MR imaging is well suited to depict the extent of disease and the relationship to adjacent structures, although evaluation of calcifications is limited.
Plasma cell Castleman disease typically demonstrates less avid enhancement after contrast administration compared with hyaline vascular Castleman disease, which makes the differentiation from reactive or neoplastic nodal involvement more difficult. Calcification is uncommon. Intralesional fibrosis and necrosis may lead to a heterogeneous appearance, especially in Plasma cell Castleman disease with lesions larger than 5 cm . The CT appearance of HHV-8–associated Castleman disease is often indistinguishable from that of plasma cell Castleman disease, although more severe systemic manifestations are generally observed.
Prognosis and treatment
Although Castleman disease was initially described as a benign localized lymphoproliferative disease, the systemic forms of Castleman disease especially are associated with an increased risk for related neoplasms of prognostic and therapeutic importance, including Kaposi sarcoma ,follicular dendritic cell tumors and non-Hodgkin lymphoma, predominantly the immunoblastic or plasmablastic B-cell lymphoma subtypes. Other associated lymphomas are Hodgkin disease and plasmacytoma (7).Hyaline vascular Castleman disease is associ-ated with follicular dendritic cell neoplasms, including dendritic cell sarcomas and vascular and stromal neoplasms. Paraneoplastic pemphigus is a debilitating chronic blistering mucocutaneous disease. The cutaneous findings may resemble those of lichen planus, pemphigus, erythema multiforme, or graft versus host disease . Para-neoplastic pemphigus is associated with occult neoplasms and Castleman disease and should be suspected in patients with treatment resistant erosive mucosal lesions).POEMS syndrome is characterized by poly-neuropathy, organomegaly, endocrinopathy, M protein, and skin changes and is a rare plasma cell disease with multisystem involvement .Between 11% and 30% of patients with POEMS syndrome have multicentric Castleman disease, most commonly the HHV-8–positive variant.
Unicentric hyaline vascular Castleman disease is often curable with surgery; treatment of multicentric Castleman disease may require steroid therapy, chemotherapy, antiviral medication, or the use of antiproliferative regimens.
References
1.Castleman B, Iverson L, Menendez VP. Localized mediastinallymphnode hyperplasia resembling thymoma. Cancer. 1956 Jul-Aug. 9(4):822-30. [Medline].
2.Cronin DM, Warnke RA. Castleman disease: an update on classification and the spectrum of associ-ated lesions. AdvAnatPathol 2009;16(4):236–246
3.Tey HL, Tang MB. A case of paraneoplasticpem-phigus associated with Castleman’s disease present-ing as erosive lichen planus. ClinExpDermatol 2009;34(8):e754–e756. Published July 29, 2009. Accessed October 3, 2010
4.Nicoli P, Familiari U, Bosa M, et al. HHV8-positive, HIV-negative multicentric Castleman’s disease: early and sustained complete remission with rituximab therapy without reactivation of Kaposi sarcoma. Int J Hematol 2009;90(3):392–396.
5.Johkoh T, Müller NL, Ichikado K, et al. Intrathoracic multicentric Castleman disease: CT findings in 12 patients. Radiology 1998;209(2):477–481.
6.McAdams HP, Rosado-de-Christenson M, Fishback NF, Templeton PA. Castleman disease of the thorax: radiologic features with clinical and histopathologic correlation. Radiology 1998;209(1):221–228.
7.Weisenburger DD, Nathwani BN, Winberg CD, Rappaport H. Multicentric angiofollicular lymph node hyperplasia: a clinicopathologic study of 16 cases. Hum Pathol 1985;16(2):162–172