Endosonographic features of unicentric Castleman Disease

BACKGROUNDCastleman disease (CD) is a rare lymphoproliferative disorder most frequently occurring in the mediastinum. Peripancreatic forms are less frequent. Few cases of endoscopic ultrasonography-fine-needle aspiration (EUS-FNA) findings of this lesion have been reported, where no real-time tissue elastography (RTTE) has been described in the literature to our knowledge. METHODSWe describe the endosonographic, elastographic, cytologic and immunocytochemistry findings in two cases of unicentric CD of the hyaline vascular variant. RESULTSTwo females, aged 41 and 34 year were referred to our hospital for further EUS evaluation of a peripancreatic mass found incidentally on computed tomography. EUS examination revealed around, well-demarcated, uniformly hypoechoic mass measuring 52 and 23 mm respectively, with smaller adjacent hypoechoic lymph nodes. Doppler examination revealed intense peripheral vascularity, together with prominent penetrating feeding vessels entering a distinct hilum. RTTE revealed a relatively homogenous soft elastographic pattern. EUS-FNA provided smears with clusters of lymphocytes in a hemorrhagic background. Cell block preparation showed immature lymphocytes surrounding lymphocyte-poor centers with vascular proliferation. Immunohistochemical staining of the cell block sections showed CD45-leukocyte common antigen, CD20, CD23, CD79a, Bcl-2 and CD5 positivity in small lymphocytes. Cytology was suggestive of non-Hodgkin's lymphoma. Surgical excision was performed in both cases and histopathology was consistent with CD of the hyaline vascular type. CONCLUSIONThe echo features of a solitary hypoechoic homogenous well-demarcated mass with prominent vasculature and increased elasticity should raise the possibility of unicentric CD. EUS-FNA usually cannot make a definitive distinction from certain kinds of lymphoma.