title: Diagnosis of primary pulmonary T- cell/histiocyte-rich large B cell lymphoma with tissue eosinophilia via clinicopathological observation and molecular assay.
abstract: BACKGROUND
  Primary pulmonary lymphoma (PPL) is rare and easily misdiagnosed because of the lack of typical clinical features. It most commonly involves elderly patients aged between 60 and 70 years, and pathological diagnosis depends mainly on chest surgery rather than bronchial mucosal biopsy. Via percutaneous needle aspiration biopsy of the lung of a 33-year-old woman, which had distinct tissue eosinophilia, we diagnosed a rare case of rapidly growing large B cell lymphoma.
  
  
  METHODS
  Bronchial mucosal biopsy and computed tomography-guided percutaneous needle aspiration biopsy were performed to determine the nature of the lesion, and we identified its immunophenotype using immunohistochemistry. We used BIOMED-2 gene rearrangement PCR to determine lymphocyte clonality; laser microdissection was used to confirm the clonality of suspicious malignant lymphocytes.
  
  
  RESULTS
  Morphologically, the lesion was composed of a large number of eosinophilic cells and a few lymphoid cells. Immunohistochemical staining revealed a few CD1α-positive cells, but they were S-100-negative. The small lymphoid cells predominantly expressed CD3; the large lymphoid cells expressed CD20 and some scattered large lymphoid cells expressed Pax5. However, molecular studies confirmed clonal immunoglobulin heavy chain (IGH)-D gene rearrangement in Pax5-positive large B lymphocytes.
  
  
  CONCLUSIONS
  This is the first recorded case of T- cell/histiocyte-rich large B cell lymphoma with tissue eosinophilia of the lung. It highlights the unusual morphological features of PPL that might be mistaken for eosinophilic granuloma or parasitic infection. In addition, IGH and T cell receptor gene rearrangement play important roles in differentiating rare B cell lymphoma from lung space-occupying lesions with abundant eosinophils or T cell infiltration.
  The virtual slide(s) for this article can be found here: http://med.motic.com/MoticGallery/Slides/AC5C9A6F-46EC-4C71-A448-1312F6900C65?user=2C69F0D6-A478-4A2B-ABF0-BB36763E8025.
authors.forename: Jin
authors.initials: J
authors.lastname: Zhu
authors.forename: Yingmei
authors.initials: Y
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Gong
authors.forename: Gaosheng
authors.initials: G
authors.lastname: Huang
mesh_terms: D000328:Adult; D018949:Antigens, CD1 / Q000378:metabolism; D018951:Antigens, CD20 / Q000378:metabolism; D001706:Biopsy; D017252:CD3 Complex / Q000378:metabolism; D015897:Comorbidity; D005260:Female; D006644:Histiocytes / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D016393:Lymphoma, B-Cell / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D016399:Lymphoma, T-Cell / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D051757:PAX5 Transcription Factor / Q000378:metabolism; D011657:Pulmonary Eosinophilia / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D020545:Respiratory Mucosa / Q000378:metabolism / Q000473:pathology
chemical_list: D018949:Antigens, CD1; D018951:Antigens, CD20; C419393:CD1a antigen; D017252:CD3 Complex; D051757:PAX5 Transcription Factor; C497281:PAX5 protein, human