title: Interobserver variation is a significant limitation in the diagnosis of Burkitt lymphoma.
abstract: BACKGROUND
  The pathology of classic Burkitt lymphoma (BL) remains a challenge despite being a well-defined entity, in view of the significant overlap with atypical BL and B-cell lymphoma intermediate between DLBL (diffuse large B cell lymphoma) and BL. They are difficult to be segregated in resource-limited setups which lack molecular testing facilities. This is further affected by interobserver variability and experience of the reporting pathologist.
  
  
  OBJECTIVE
  The aim of our study was to quantitate variability among a group of pathologists with an interest in lymphomas (albeit with variable levels of experience) and quantitate the benefit of joint discussions as a tool to increase accuracy and reduce interobserver variability of pathologists, in the diagnosis of BL in a resource-limited setup.
  
  
  METHODS
  A set of 25 non-Hodgkin lymphoma cases in which a diagnosis of BL was entertained were circulated to 14 participating pathologist within the Mumbai lymphoma study group. A proforma recorded the morphologic and immunohistochemical features perceived during the initial independent diagnosis followed by a consensus meeting for discussion on morphology and additional information pertinent to the case.
  
  
  RESULTS
  The concordance was poor for independent diagnosis among all the pathologists with kappa statistics (±SE) of 0.168 (±0.018). Expert lymphoma pathologists had the highest (albeit only fair) concordance (kappa = 0.373 ± 0.071) and general pathologists the lowest concordance (kappa = 0.138 ± 0.035). Concordance for morphological diagnosis was highest among expert lymphoma pathologists (kappa = 0.356 ± 0.127). Revision of diagnoses after consensus meeting was highest for B-cell lymphoma intermediate between DLB and BL. To conclude, interobserver variation is a significant problem in BL in the post WHO 2008 classification era. Experience with a larger number of cases and joint discussion exercises such as the one we conducted are needed as they represent a simple and effective way of improving diagnostic accuracy of pathologists working in a resource-limited setup.
authors.affiliation: Department of Pathology, Tata Memorial Centre, Mumbai, India.
authors.forename: Swapnil Ulhas
authors.initials: SU
authors.lastname: Rane
authors.affiliation: Department of Pathology, Tata Memorial Centre, Mumbai, India.
authors.forename: Tanuja
authors.initials: T
authors.lastname: Shet
authors.affiliation: Department of Pathology, Tata Memorial Centre, Mumbai, India.
authors.forename: Epari
authors.initials: E
authors.lastname: Sridhar
authors.affiliation: Department of Pathology, Prince Aly Khan Hospital, Mumbai, India.
authors.forename: Sanica
authors.initials: S
authors.lastname: Bhele
authors.affiliation: Department of Pathology, L.T. Medical College and Sion Hospital, Mumbai, India.
authors.forename: Vaishali
authors.initials: V
authors.lastname: Gaikwad
authors.affiliation: Department of Pathology, Grant Medical College and Sir J. J. Hospital, Mumbai, India.
authors.forename: Shubhangi
authors.initials: S
authors.lastname: Agale
authors.affiliation: Department of Pathology, T.N. Medical College and Nair Hospital, Mumbai, India.
authors.forename: Sweety
authors.initials: S
authors.lastname: Shinde
authors.affiliation: Department of Pathology, Seth G.S. Medical College and K.E.M. Hospital, Mumbai, India.
authors.forename: Daksha
authors.initials: D
authors.lastname: Prabhat
authors.affiliation: Department of Pathology, Seth G.S. Medical College and K.E.M. Hospital, Mumbai, India.
authors.forename: Gwendolyn
authors.initials: G
authors.lastname: Fernandes
authors.affiliation: Department of Pathology, Lilavati Hospital, Mumbai, India.
authors.forename: Meenal
authors.initials: M
authors.lastname: Hastak
authors.affiliation: Department of Pathology, Lilavati Hospital, Mumbai, India.
authors.forename: Chandralekha
authors.initials: C
authors.lastname: Tampi
authors.affiliation: Dr. Narurkar's Laboratory, Mumbai, India.
authors.forename: Swati
authors.initials: S
authors.lastname: Narurkar
authors.affiliation: Department of Pathology, Bombay Hospital, Mumbai, India.
authors.forename: Keyuri
authors.initials: K
authors.lastname: Patel
authors.affiliation: Department of Pathology, Hinduja Hospital, Mumbai, India.
authors.forename: Chitra
authors.initials: C
authors.lastname: Madiwale
authors.affiliation: Department of Pathology, Nanavati Hospital, Mumbai, India.
authors.forename: Ketki
authors.initials: K
authors.lastname: Shah
authors.affiliation: Department of Pathology, Nanavati Hospital, Mumbai, India.
authors.forename: Laxmi
authors.initials: L
authors.lastname: Shah
authors.affiliation: Tata Medical Centre, Kolkatta, India.
authors.forename: Satyakam
authors.initials: S
authors.lastname: Sawaimoon
authors.affiliation: Specialty Ranbaxy Ltd, Mumbai, India.
authors.forename: Purnima
authors.initials: P
authors.lastname: Lad
keywords: Burkitt lymphoma; concordance; inter-observer variation; non-Hodgkin lymphoma