14 March 2022: Textbook Updates

We have posted updates of the following topics:

Bone & joints > General > Biopsy
by Borislav A. Alexiev, M.D.
Topic summary: Procedure in which bone samples are removed with a special biopsy needle or obtained during surgery to find out if cancer or other abnormal cells are present. There are 3 types of bone biopsies: open (surgical) biopsy, core needle biopsy and fine needle aspiration biopsy. Biopsy is the most critical first step in determining treatment strategy and outcomes in the management of musculoskeletal lesions. Biopsy must be carefully planned to ensure that adequate diagnostic tissue is obtained without compromising the oncologic outcome. Open (surgical) biopsy has historically been the diagnostic standard.

Colon > Molecular > POLD1 / POLE
by Neha Varshney, M.D., Varsha Prakash, M.D., M.S.
Topic summary: Germline missense pathogenic variants in the exonuclease domain (ED) of polymerases epsilon (POLE) and delta (POLD1) affect their proofreading capabilities, predisposing to multiple colorectal adenomas and carcinomas. Deleterious mutations in the proofreading exonuclease domain of POLE occur in approximately 7 – 12% of endometrial carcinomas, 1 – 2% of colorectal carcinomas and a small number of other cancer types. POLE / POLD1 mutations have beneficial clinical outcomes post immune checkpoint inhibitor (ICI) therapy in endometrial cancer, non small cell lung cancer, CRC and cervical carcinosarcoma.

Liver & intrahepatic bile ducts > Benign / nonneoplastic > Segmental atrophy
by Elaina Daniels, M.D., Naziheh Assarzadegan, M.D.
Topic summary: Rare, underrecognized benign entity, which can present as a mass lesion (pseudotumor). Pathophysiology involves a possible vascular injury and ischemia with subsequent elastin remodeling by liver myofibroblasts. Variable age range (3 – 91 years old) with the majority presenting in the fifth to sixth decades of life. Can present with right upper quadrant pain, ascites or a palpable abdominal mass or it may be discovered incidentally in an asymptomatic patient. Benign condition with favorable prognosis. Treatment: complete excision of the lesion.

Liver & intrahepatic bile ducts > Metabolic diseases > Wilson disease
by ILKe Nalbantoglu, M.D., Paul DiDomenico, M.D., M.B.A., M.S.
Topic summary: Increased / toxic copper deposition within liver, cornea, kidney and central nervous system. Also known as hepatolenticular degeneration. Autosomal recessive inheritance (ATP7B mutation). Incidence of 1:30,000 individuals; geographic variations exist. Suspect Wilson disease in children and adults with unexplained liver enzyme elevations; diagnosis may be challenging. Treatment: D penicillamine and trientine – oral chelating agents.

Molecular markers > Tumor mutation burden
by Megan Parilla, M.D.
Topic summary: An accounting of the number of somatic mutations seen in a particular tumor’s genome. Tumor mutation burden (TMB) is one of the biomarkers that suggests whether immune checkpoint inhibition therapy will be efficacious. FDA has approved pembrolizumab (a PD-1 inhibitor) for solid tumors that are unresectable or metastatic and are categorized as TMB H. TMB has a mixed impact on prognosis when separated from immunotherapy response. TMB was initially described in whole exome sequencing (WES), a form of next generation sequencing (NGS), which is the gold standard. Compared to WES, targeted gene panels have the advantage of faster turnaround times, lower costs and broader availability.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s