All posts by peferguson

Neoplastic Lung Classification – Resection Specimens

November 3, 2017 peferguson

The following is a combination of the IASLC/ATS/ERS lung tumor classification for adenocarcinoma in resection specimens and the general WHO 2004 classification. See Neoplastic Lung Classification – Biopsy for categorization in small biopsy samples.

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Organ Systems, Pulmonary

Neoplastic Lung Classification – Biopsies

November 3, 2017 peferguson

Recommended IASLC/ATS/ERS terminology for tumor diagnoses on small lung biopsies . See Neoplastic Lung Classification – Resection Specimens for categorization of large excision specimens.

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Organ Systems, Bone Marrow, WHO Classification, MDS, MDS/MPN

Dysplasia Characteristics

November 1, 2017 peferguson

Identification of dysplasia in >10% of a particular hematologic lineage is an important defining criteria for myelodysplasia (MDS) in a bone marrow specimen. The following are the described agreed upon features of dysplasia per the WHO Classification. Continue reading Dysplasia Characteristics →

Organ Systems, Bone Marrow, WHO Classification, MDS

Cytopenia Definition

November 1, 2017 peferguson

WHO Criteria for Cytopenias

Platelet count <100,000/μL
Hemoglobin <10g/dL
Absolute neutrophil count <1,800/μL

The WHO Classification does state patients with MDS may present having mild cytopenias with values above the defined levels. Continue reading Cytopenia Definition →

Organ Systems, Bone Marrow, WHO Classification, MDS, MDS/MPN

SB3F1 Mutation

November 1, 2017 peferguson

SB3F1 is a RNA splicesome, mutated SB3F1 may result in an alternative function proteins instead of a loss of function mutation (Obeng, et al.)
Point mutations associated with MDS are in the regions of exons 14 to 16
~25% of all cases of MDS have a SB3F1 mutation
~80% of MDS-RS SLD have SBF3F1 mutation
30-70% of MDS-RS MLD have SB3F1 mutation
20% of MDS/MPN cases have SB3F1 mutation
Heterozygous mutation of SB3F1 mutation is associated with disease
Obeng et al. demonstrated in mice that an isolated SB3F1 mutation is sufficient to cause MDS-type findings
The presence of a SB3F1 mutation has a positive predictive value (PPV) of finding ring sideroblasts of 97.7%.

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Organ Systems, Bone Marrow, WHO Classification, MDS, MDS/MPN

Ring Sideroblasts

November 1, 2017 peferguson

Definition

≥5 iron staining granules (+)
Encircling at least 1/3 of the nucleus

Diagnostic criteria for significant in MDS are ≥15% ring sideroblasts without evidence (or knowledge) of a SB3F1 mutation. This threshold drops to ≥5% with a SB3F1 mutation) Continue reading Ring Sideroblasts →