Figure 1

Histopathological findings. (A) The bone marrow appeared hypercellular with a marked expansion of granulopoiesis and a moderate increase of megakaryocytes (Periodic acid–Schiff (PAS), 20X). (B) On sections stained with the Gomori's silver impregnation technique, a diffuse and dense increase in reticulin with extensive intersections, occasionally with only focal bundles of collagen was evident. Fiber density was considered as grade 2 according to the European Consensus Criteria for grading myelofibrosis by Thiele et al. [2] (20X). (C,D) Multiple fragments of lymph node tissue were excised from the mediastinum of this patient. The architecture was preserved, showing CD20+ B-follicles and germinal centers with onion-skin appearance around prominent arterioles. The interfollicular areas showed abundant plasma cells with normal kappa:lambda ratio. Immunohistochemistry did not reveal aberrant B- or T-cell phenotype. Molecular testing was negative for B-cell or T-cell monoclonality. The search for HHV8 and EBV was also negative. The histology pattern was considered not diagnostic for malignant lymphoma and related to a lymphadenopathy with features resembling multicentric Castleman’s disease. The diagnosis was reviewed at the referral center of Bologna (Prof. Pileri) and confirmed.