CPC #1 Pathology Right lung (unfixed) Multiple nodules in left - PDF document

CPC #1 Pathology

Right lung (unfixed)

Multiple nodules in left lung (fixed)

Left lung (fixed)

Multiple Pulmonary Nodules • Vascular – Vasculitis (Wegener’s) – Pulmonary infarction • Infection – Bacteria • Mycobacteria – Fungus • Neoplasms – Primary • Benign • Malignant – Metastatic

Malignant Neoplasms • Carcinomas • Sarcomas • Melanoma • Germ Cell Tumors • Leukemia/Lymphoma

Characterizing an Poorly- Differentiated Malignancy • Immunohistochemistry – Stain slides with antibodies to proteins that are specific to certain cell types • Electron Microscopy – Special microscope for extremely high resolution • Genetics – Cytogenetics – Molecular Biology

CD20 (B cell marker)

CD20 (B cell marker)

CD3 (T cell marker)

Ki-67 (Proliferation marker)

Diffuse Large B Cell Lymphoma Diagnosis

DIAPHRAGM IMPLANT

DIAPHRAGM IMPLANT

EPIDIDYMIS

EPIDIDYMIS

HEART-RIGHT ATRIUM

HEART-RIGHT ATRIUM

LEFT VENTRICLE

Diagnosis • Diffuse Large B Cell Lymphoma, involving – Lungs (bilateral nodules) – Middle Mediastinum – Paratesticular soft tissue (bilateral) – Diaphragm – Heart • Cardiomegaly • Atherosclerosis, Aorta

Extranodal Lymphoma • Lymphoma arising outside of lymph nodes – Lymphocytes normally circulate – Found in small numbers in virtually all organs • 25% of Non-Hodgkins lymphomas are extranodal • Uncommon in Hodgkins lymphoma

Common Extranodal Lymphomas • Low Grade – B cell • Mucosa Associated Lymphoid Tissue (MALT) type – Stomach (H. pylori) – Salivary gland (Sjogren’s syndrome) – Thyroid (Hasimoto’s thyroiditis) – T cell • Mycosis fungoides of skin

Common Extranodal Lymphomas (cont) • High Grade – B cell • Diffuse Large B Cell Lymphoma – Common sites include lung, GI tract, CNS – Can be solitary or multifocal – Can be associated with immunosuppression • Burkitt lymphoma – Commonly involves ileocecal area in children – T cell • Peripheral T Cell Lymphomas

Summary-Key Points • Diffuse Large B Cell Lymphoma is the most common high grade extranodal lymphoma • Differential diagnosis of disseminated malignancy • Immunohistochemistry can be used to characterize a poorly-differentiated malignancy