Ans) a (Easily...) Ref: Sabiston 18th ed, 17th ed p890, Robbins 7th ed p 1144Invasive lobular carcinoma (ILC) may be found by mammography, However, ILCdoes not always show up well on a mammogram because of the cells' tendency to grow in a single-file line, rather than form a mass. If mammogram does find invasive lobular carcinoma, the tumor may appear smaller than it actually is. Whenever a screening mammogram highlights an area of concern, additional mammograms often will be done to gather more information about that area. Mammography will be performed on both breasts. So ILC is difficult to detect in mammogram.Infiltrating lobular carcinomaInfiltrating lobular carcinoma accounts for about 5 percent of all malignant invasive cancers. It occurs most frequently in women between the ages of 45 and 56. The tumor grows in the terminal (last part) of the lobules where milk is produced. It usually does not show up on mammography and may feel like a thickening in the upper-outer quarter of the breast (from the nipple to under the arm) as it infiltrates the walls of the lobules.In about 30% of cases, this cancer is frequently found in the opposite breast.It is often found in other parts of the same breast (multicentric).Most tumors are positive for estrogen and progesterone receptors and thus respond well to hormonal therapy.Infiltrating lobular carcinoma sometimes has an increased incidence of spreading to the uterus and ovaries.Lobular carcinoma in situ (LCIS) occurs bilaterally in 50 70% of cases, while ductal carcinoma in situ (DCIS) occurs bilaterally in 10 - 20% of cases.Invasive lobular carcinomaFrequently multifocal, multicentric and bilateral.Incidence increased in post menopausal women (related to post menopausal HRT)Histological hallmark - pattern of single infiltrating tumor cells, often only one cell in width (Indian File Pattern) or in loose clusters or sheets.Most lobular carcinoma show a loss of a region on chromosome 16 (e-cadherin and b catenin genes are lost)Lobular carcinoma have a different pattern of metastasis compared to other breast carcinoma (less likely to metastasis to lung and pleura)Well/moderately differentiated lobular carcinomaDiploidExpress hormone receptorsAssociated with LCIS in majority of casesHER 2/neu over expression is very rare.Poorly differentiated lobular carcinomaAneuploidOften lack hormone receptorsMay over express HER 2/neuUltrasound bounces sound waves off of the breast to create additional images of the tissue. Ultrasound can be used in addition to mammography. Ultrasound appears to be more accurate in detecting invasive lobular carcinoma than mammography. As with mammography, however, the tumor may appear smaller than it is.Note:Breast carcinoma with good prognosis even with axillary lymph nodes - medullary CaBulls eye appearance is seen in - invasive lobularDesmoplastic reaction is shown by - ductalComedo carcinoma is - ductal carcinoma in situ (DCIS)Most common variant of breast carcinoma - Ductal invasive