Understanding the Pathology Report
The following terms and abbreviations are common to most pathology reports. An
understanding of their meanings will help patients better understand their diagnosis and
pathology.
The first two lists contain breast cancer histologic and histopathologic classifications [1-2]
Histology is the study of the microscopic structure of tissue.
Ductal Carcinoma
Intraductal (in situ)
Invasive with predominant intraductal component
Invasive, NOS (not otherwise specified)
Comedo
Inflammatory
Medullary with lymphocytic infiltrate
Mucinous (colloid)
Papillary
Scirrhous
Tubular
Other
Lobular Carcinoma
In situ
Invasive with predominant in situ component
Invasive
Nipple Carcinoma
Paget's disease, NOS (not otherwise specified)
Paget's disease with intraductal carcinoma
Paget's disease with invasive ductal carcinoma
Undifferentiated Carcinoma
Cystosarcoma phyllodes
Inflammatory carcinoma
Other
Source:
1. Physician Data Query (PDQ) January 24, 1994, modified
2. Breast. In: American Joint Committee on Cancer: Manual for Staging of Cancer. Philadelphia: JB Lippincott Co., 4th Ed., 1992,pages 149-154, modified.
The following is a list of breast cancer histologic classifications:
Histopathologic Grade {G} [3]
GX = Grade cannot be assessed
G1 = Well differentiated
G2 = Moderately differentiated
G3 = Poorly differentiated
G4 = Undifferentiated
Source:
3. World Health Organization (WHO) modified.
Staging
The following list contains staging information.
Staging is the process of classifying tumors, especially malignant tumors, based on the histologic and histopathologic
information previously described.
Staging helps to determine the following information about a tumor:
Degree of cell differentiation
Potential for responding to treatment
Prognosis
Treatment decisions are influenced in part according to staging categories.
The main factors influencing treatment decisions include:
•Lymph node status
•Estrogen receptor (ER) and progesterone receptor (PR) receptor levels in the tumor tissue
•Menopausal status (pre-,peri-,post-menopausal)
•Overall health status of the patient
Stages are defined by the TNM classification [1], which is the most widely accepted
staging system used to determine the extent and prognosis of tumors. TNM stands for
tumor, node and metastasis. Numbers are added to each of these categories to indicate
the degree of dissemination or spread of disease.
Dissemination is a term applied to disease organisms scattered or distributed throughout
an organ or body. [4]
Source and Suggested Resource:
1. Physician Data Query (PDQ) January 24, 1994, modified
2. Taber's Cyclopedic Medical Dictionary, 1993, F.A. Davis Company, modified.
TNM Definitions [1]
Primary Tumor (T)
TX = Primary tumor cannot be assessed
T0 = No evidence of primary tumor
Tis = Carcinoma in situ, intraductal carcinoma, lobular carcinoma in situ or Paget's
disease of the nipple with no associated tumor mass. (Paget's disease associated with
tumor mass is classified according to the size of the tumor.)
T1 = Tumor size of 2.0 centimeter (cm) or less in greatest dimension.
(Dimpling of the skin, nipple retraction or other skin changes may occur in T1 without changing the classification.)
T1a = 0.5 cm but not more than 1.0 cm in greatest dimension
T1b = More than 0.5 cm but not more than 2.0 cm in greatest dimension
T1c = More than 1.0 cm but not more than 2.0 cm in greatest dimension
T2 = Tumor more than 2.0 cm but not more than 5.0 cm in greatest dimension.
(Dimpling of the skin, nipple retraction or other skin changes may occur in T2 without changing
the classification.)
T3 = Tumor more than 5.0 cm in greatest dimension.
(Dimpling of the skin, nipple retractionor other skin changes may occur in T3 without changing the classification.)
T4 = Tumor of any size with direct extension to chest wall or skin (chest wall includes
ribs, intercostal muscles and serratus anterior muscle, but not pectoral muscle).
T4a = Extension to chest wall
T4b = Edema, ulceration of the skin of the breast or satellite skin nodules confined to
the same breast
T4c = Both T4a and T4b
T4d = Inflammatory carcinoma
Source: 1. Physician Data Query (PDQ) January 24, 1994,
modified
Regional Lymph Nodes (N)
NX = Regional lymph nodes cannot be assessed (may have been previously removed)
N0 = No regional lymph node metastasis
N1 = Metastasis to movable ipsilateral* axillary lymph node(s)
N2 = Metastasis to ipsilateral lymph node(s) fixed to one another or to other structures
N3 = Metastasis to ipsilateral internal mammary lymph node(s)
* Ipsilateral lymph node(s) = on the same side; affecting the same side of the body
Distant Metastasis (M)
MX = Presence of distant metastasis cannot be assessed
M0 = No distant metastasis
M1 = Distant metastasis present (includes metastasis to ipsilateral supraclavicular*
lymph nodes)
* Supraclavicular lymph nodes = located above the clavicle (collarbone)
Source:
1. Physician Data Query (PDQ) January 24, 1994, modified
The four (4) stages of breast cancer are defined by the following TNM
Groups:
Stage Grouping of Primary Tumor Regional Nodes and Distant
Metastasis by TNM Groups
Stage 0 (in situ)
Tis, N0, M0
Stage I
T1, N0, M0
Stage II
Stage IIA
T0, N1, M0
T1, N1, M0
T2, N0, M0
Stage IIB
T2, N1, M0
T3, N0, M0
Stage III
Stage IIIA
T0, N2, M0
T1, N2, M0
T2, N2, M0
T3, N1, M0
T3, N2, M0
Stage IIIB
T4, any N, M0
Any T, N3, M0
Stage IV (Inflammatory)
T4d
