Neoplastic
Non-Neoplastic
- Lymph Nodes
- Extra-Nodal
- Bone Marrow
- Peripheral Blood
- Spleen
Category Archives: Organ Systems
Breast – Collagenous Spherulosis
Collagenous Spherulosis is an uncommon incidental benign finding, which can be confused with other pathologies such as DCIS, carcinoma, and adenoid cystic carcinoma of the breast.
The lesions are characterized by central mucin with epithelial cells (luminal and myoepithelial) radially arranged at the periphery.
Photomicrographs
References
Resetkova, E., et. al. “Collagenous spherulosis of breast: morphologic study of 59 cases and review of the literature.”. Am J Surg Pathol. 30 (1):207. Jan 2006. doi:10.1097/01.pas.0000179237.91515.81
Breast – Fat Necrosis
Fat necrosis may sometimes present as a palpable mass, which may raise clinical concern or distress in the patient. Approximately 1/2 of cases have a history of trauma. Fat necrosis is also a common finding in excision specimen after a preceding biopsy.
The characteristic findings of fat necrosis include mixed inflammation (neutrophils, histiocytes, etc.), fibroblastic proliferation, and liquefactive fat necrosis. Each of the component may vary in prominence. The most important thing is not to mistake fat necrosis for malignancy, and not miss an area of malignancy masked by fat necrosis (AE1/AE3 or CAM5.2 may be helpful in such situations).
Photomicrographs
References
Kumar, Vinay, Abul K. Abbas, and Jon C. Aster. Robbins and Cotran Pathologic Basis of Disease. Ninth edition. Philadelphia, PA: Elsevier/Saunders, 2015.
Breast – Epithelial Proliferations
There are many features of breast disease that encompass a wide spectrum of morphologic and radiologic findings, which have a varying risk of subsequent carcinoma. Some of these entities are thought to be direct precursors to invasive carcinoma, and others just signify a component of future risk of invasive carcinoma.
Non-Atypical Lesions
- Fibrocystic Change
- Usual Type Hyperplasia (UTH)
- Sclerosing Adenosis
- Complex Sclerosing Lesion/Radial Scar
- Intraductal Papilloma
- Fibroadenoma
Miscellaneous Findings
Atypical Lesions
Breast Lesions and Risk of Developing an Invasive Carcinoma
Breast Immunohistochemsitry
Breast – IHC
There are multiple situations where immunohistochemistry can serve an important role in breast disease. These include: differentiation of lesion types (e.g. UTH vs. ADH), identifying invasion (e.g DCIS vs. DCIS with invasion), and predictive/prognostic information (e.g. ER/PR/HER-2).
Breast Lesions and Risk of Developing an Invasive Carcinoma
The following table and figure illustrate the risk of developing an invasive breast carcinoma based on the type of lesions previously identified. This information does not take into consideration other factors such as race and family history (complicated topic).
Relative and Absolute Risk of Invasive Breast Carcinoma
|
Relative
Risk
|
Absolute
Risk
(lifetime)
|
Breast
Lesion
|
|
1
|
3%
|
|
|
1.5 – 2
|
5-7%
|
|
|
4 – 5
|
13-17%
|
|
|
8 – 10
|
25-30%
|
References
Kumar, Vinay, Abul K. Abbas, and Jon C. Aster. Robbins and Cotran Pathologic Basis of Disease. Ninth edition. Philadelphia, PA: Elsevier/Saunders, 2015.
Breast
Non-Neoplastic/Pre-Neoplastic Disorders
- General
- Developmental
- Inflammatory
- Epithelial Proliferations
- Breast Lesions and Risk of Carcinoma
Endometrial vs. Endocervical Adenocarcinoma
Endocervical vs. Endometrial Adenocarcinoma
Endocervical and endometrial adenocarcinomas may be morphologically indistinguishable morphologically. The question often comes up as to whether a case represents an endometrial adenocarcinoma involving the cervix, or and endocervical adenocarcinoma involving the endometrium. The following antibodies may be helpful in such circumstances:
|
|
Endocervical
Adenocarcinoma
|
Endometrial
Adenocarcinoma
|
|
Negative (7-8%+)
|
Positive (70-93%)
|
|
|
Positive (65-95%)
|
Usually Negative
|
|
|
Negative (4-20%+, 38% weak)
|
Strong Positive (67-90%)
|
|
|
Strong & Diffuse Positive (90-100%)
|
Patchy Positive cells (~35%)
|
|
|
HPV
|
Positive (67%)
|
Negative
|
References
AJSP 2002;26:998
“Endocervical vs. Endometrial Adenocarcinoma: Update on Useful Immunohistochemical Markers.” RT Miller,The Focus ProPath Immunohistochemistry.” April 2003.
Mesothelioma vs. Adenocarcinoma
Immunohistochemistry
It is generally recommended to perform two mesothelioma markers and two carcinoma markers, since there is no single sensitive and specific marker for either entity. The data below is a snapshot of several studies.
|
IHC Marker
|
Adenocarcinoma
|
Mesothelioma
|
|
8%
|
100%
|
|
|
CK5/6 (CK5)
|
2%
|
100%
|
|
0%
|
93%
|
|
|
Thrombomodulin
|
14%
|
61-77%
|
|
N-Cadherin
|
30%
|
73%
|
|
93-100%
|
8%
|
|
|
80-100%
|
18%
|
|
|
BG8
|
96%
|
7%
|
|
81-88%
|
0%
|
|
|
84%
|
0%
|
|
|
72-74%
|
0%
|
|
|
72-85%
|
0%
|
Obviously the main source of adenocarcinoma in this differential setting is with a primary lung adenocarcinoma and mesothelioma. If a metastasis is likely, then the stain performance expectations for adenocarinoma may vary significantly (e.g. metastatic ovarian serous carcinoma would likely express WT-1).
References
Marchevsky AM. Application of immunohistochemistry to the diagnosis of malignant mesothelioma. Arch Pathol Lab Med. 2008;132: 397–401.
Sandeck HP, Røe OD, Kjærheim K, Willén H, Larsson E. Re-evaluation of histological diagnoses of malignant mesothelioma by immunohistochemistry. Diagnostic pathology. 2010;5: 47. doi:10.1186/1746-1596-5-47
Ordóñez NG. Immunohistochemical diagnosis of epithelioid mesothelioma: an update. Arch Pathol Lab Med. 2005;129: 1407–1414.
Urothelial Carcinoma
Urothelial carcinoma is the primary tumor in the bladder. It may have morphologies or adenocarcinoma, urothelial carcinoma (transitional), or squamous cell carcinoma.
IHC Expression Characteristics
|
CK7 is expressed in a majority of urothelial carcinomas. (CK7+/CK20+) Bladder adenocarcinomas with intestinal differentiation may lose CK7 expression.
|
|
|
(++/-) Wide variation in reported expression (15-97%), but appears a majority are positive (CK7+/CK20+). There is some evidence that CK20 may be helpful in CIS dx. Reactive urothelium shows CK20 expression in the umbrella cells. Most dysplasia/CIS cases show at least focal transmural CK20 expression. Sensitivity and specificity for CK20 have been shown to be >70% and >90%, respectively. (Ki-67. p53, & p16 may also be useful)
|
|
|
p63 staining is found in >90% of urothelial layer nuclei. PSA combined with p63 may be a helpful combination to differentiate a primary prostate tumor from urothelial carcinoma.
|
|
|
34betaE12
CK5/6
|
HMWK which is expressed in the basal layer of prostate glands, and urothelium (highly sensitive). Practically any tumor with squamous differentiation will usually express HMWKs.
|
|
p53
|
Expression found in 40-60% of bladder carcinomas (worse prognosis). Expression of p53 in >50% of cells is seen in CIS, whereas reactive urothelium show weak patchy nuclear staining.
|
|
Increased expression in flat CIS and low grade tumors.
|
|
|
CD44
|
May be useful in that it is normally expressed in the basal layer, and is absent in full thickness CIS.
|
|
Often positive in urothelial dysplasia.
|
References
Diagnostic Immunohistochemistry: Theranostic and Genomic Applications. [edited by] DJ Dabbs. 3rd Edition. Elsevier, 2010.