a 77yearold man complained of slight shortness of breath , and was referred to our hospital due to enlarging mediastinal / hilar lymphadenopathy with calcification and right pleural effusion on computed tomography ( ct ) ( fig .
chest ct on parenchymal ( a ) and mediastinal ( b ) window settings showed right pleural effusion and mediastinal / hilar lymphadenopathy with calcification .
what is the appropriate procedure to approach this lesion , and what is the differential diagnosis ?
endobronchial diagnosis at nagoya medical center was requested and endobronchial ultrasoundguided transbronchial needle aspiration ( ebustbna ) of lymph node station 7 was performed .
pathological examination revealed amorphous eosinophilic tissue with few cellular components ( figs . 2 and 3a , b ) .
( if the plasma cell rate is more than 10% , myeloma can be diagnosed . ) as a result , monoclonal gammopathy of undetermined significance ( mgus ) associated with mediastinal amyloidosis was diagnosed .
echocardiography showed an ejection fraction of 45% , and there was brightness in part of the interventricular septum .
cytology of the lymph node . a lump of amorphous light green material ( papaniclaou staining , 200 ) .
( a ) section showing amorphous eosinophilic materials with hematoxylin  eosin staining ( h&e , 200 ) .
( b ) these materials stained positive for direct first scarlet staining ( dfs , 200 ) , indicating amyloid deposits .
we are currently administering combination therapy of bortezomib , melphalan , and prednisolone to this patient . as a result ,
the serum igg has decreased and there is no systemic aggravation ; however , his cardiac function has not improved with this treatment . as jenkins et al
. stated , amyloidosis should be considered in the differential diagnosis of a large mediastinal mass , especially if calcification and/or plasma cell neoplasm is present 1 .
 key clinical messagea 77yearold man was referred to our hospital due to enlarging mediastinal / hilar lymphadenopathy with calcification . 
 endobronchial ultrasoundguided transbronchial needle aspiration ( ebustbna ) and bone marrow aspiration were performed . 
 subsequently , monoclonal gammopathy of undetermined significance ( mgus ) associated with mediastinal amyloidosis was diagnosed . 
 we hereby report a case in which ebustbna led to a successful diagnosis of amyloidosis . 
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