Human herpes virus 8 (HHV-8) is a γ-herpesvirus that infects lymphocytes, bone marrow stromal cells, endothelial cells and keratinocytes, and is implicated as an etiology in multiple neoplastic conditions (usually associated with immunodeficiency). Kaposi’s sarcoma was the first described entity (1994), which was closely associated with HIV infection. While there is still a close association of HHV-8 driven neoplasms with HIV, this is certainly not an exclusive relationship. Interestingly, most of the HHV-8 lymphoproliferative disorders have plasmabalstic differentiation (helpful hint to evaluate for HHV-8 in such cases, especially if associated with immunodeficiency).
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Bladder-Small Cell Carcinoma
Small cell carcinoma (poorly differentiated neuroendocrine carcinoma) of the bladder is uncommon, but well documented. Small cell carcinoma can essentially occur at any site. Continue reading Bladder-Small Cell Carcinoma
Mammaglobin
Mammaglobin is an antibody that marks breast duct-lobular epitheliam, salivary gland epithelium, & skin eccrine epithelium. In neoplastic tissue is may stain cases of breast carcinoma, salivary gland tumors, endocervical CIS, and endometiral carcinoma. GCDFP-15 performs a little better than mammaglobin, and may have a better specificity profile.
Podoplanin
Podoplanin is a less common mesothelial and lymphatic marker that was originally used to identify glomerular structures (podocytes) in rats. It has similar perfomance characteristics to D2-40, but has less literature and experience available documenting sensitivity and specificity.
MART-1/Melan-A
MART-1/Melan-A has an expression pattern very similar to HMB-45, and these stains are often used interchangeably. It is a sensitive and specific marker for melanocytes and melanocytic derived neoplasms. Like HMB-45, MART-1 is NOT as sensitive compared to S-100 in detecting melanomas with spindled morphology.
LEF1
Lymphoid enhancer-binding factor 1 (LEF1) is a mediator of the Wnt/β-catenin pathway, which regulates cell proliferation and survival, and shows nuclear expression by immunohistochemistry. It is normally expressed in T cells and pre-B cells. Mature B cells do not express LEF1.
DLBCL – Anaplastic Variant
The anaplastic variant of diffuse large B-cell lymphoma (DLBCL) is a morphologic variant under the DLBCL, NOS category in the WHO Classification. Typical common features include:
- Marked nuclear pleomorphism, often confused with poorly differentiated carcinoma.
- Large and significantly enlarged neoplastic cells.
- May resemble Hodgkin lymphoma or anaplastic large cell lymphoma (ALCL).
PathMD icon for iPhone or Android
We have redesigned the PathMD website to not only be responsive to whatever environment (smart phone, tablet, computer) one may have available, but to be specifically optimized for smart phones. We know most people have their smart phone available a much higher portion of the time than access to a full-size desktop computer. Continue reading PathMD icon for iPhone or Android
MF2 – Reticulin Fibrosis
Diffuse increase of reticulin fibers with increased density and numerous intersections. Focal bundles of thick fibers. Continue reading MF2 – Reticulin Fibrosis
MF0 – Reticulin Fibrosis
Scattered linear fibers without intersections. Normal bone marrow.