Concordance between transbronchial lung cryobiopsy and surgical lung biopsy in patients with idiopathic multicentric Castleman disease: A report of four cases

Background: Idiopathic multicentric Castleman disease (iMCD) is a rare polyclonal lymphoproliferative disease often associated with pulmonary involvement. Recently, transbronchial lung cryobiopsy (TBLC) has been reported to be useful for the diagnosis of diffuse interstitial lung disease. However, there have been no reports of pathological assessment of TBLC for iMCD. Method: To clarify the efficacy of TBLC in the diagnosis of iMCD, we retrospectively reviewed four iMCD patients who had undergone both TBLC and surgical lung biopsy (SLB). Results: The median age was 44 years; 2 males and 2 females. Two or three TBLC specimens were taken from each patient. All patients had no complications other than minimal bleeding. The size of the TBLC specimens was approximately 5-6 x 3-4 mm, and the alveolar region, and centrilobular and perilobular areas were adequately sampled. As with SLB, the extent of lung lesions and inflammatory cell infiltration could be sufficiently evaluated by TBLC. The presence of lymphoid follicles could also be assessed by TBLC; however, the germinal centers with lymphoid follicles were difficult to evaluate. The TBLC specimens could also be evaluated for immunostaining, especially IgG4 immunostaining, to rule out IgG4-related lung disease. Pulmonary pathological grading showed a high concordance rate between major pathological findings of TBLC and SLB. The pathologist's confidence level of TBLC for the diagnosis of iMCD was high in all cases.