WBR0830

Author	[[PageAuthor::Yazan Daaboul, M.D. (Reviewed by Yazan Daaboul, M.D.)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Pathology
Sub Category	SubCategory::General Principles
Prompt	[[Prompt::A pathologist is studying the process of healing in rats. Following acute injury, he demonstrates that inflammatory cells produce growth factors that help in wound healing. Growth factors are capable of stimulating specific cells to migrate to the site of the wound. During the proliferation stage of wound healing, which immunohistochemical stain will most likely be strongly positive?]]
Answer A	AnswerA::Desmin
Answer A Explanation	AnswerAExp::Desmin is a stain for muscle cells.
Answer B	AnswerB::Cytokeratin
Answer B Explanation	AnswerBExp::Cytokeratin is a stain for epithelial cells.
Answer C	AnswerC::GFAP
Answer C Explanation	AnswerCExp::GFAP is a stain for neuroglia.
Answer D	AnswerD::Neurofilaments
Answer D Explanation	AnswerDExp::Neurofilaments is a stain for neurons.
Answer E	AnswerE::Vimentin
Answer E Explanation	AnswerEExp::Vimentin is a stain for connective tissue, including fibroblasts.
Right Answer	RightAnswer::E
Explanation	[[Explanation::Early wound healing is characterized by the presence of the inflammatory cells that produce growth factors to stimulate the migration and proliferation of fibroblasts. Fibroblasts are secretory cells that produce extracellular matrix abundant in collagen. Later during the healing process (proliferation stage) , fibroblasts then differentiate into myofibroblasts to start the process of contracture. Eventually, myofibroblasts normally disappear. Their persistence at the site is associated with cancers, fibromatoses, and fibrotic diseases. Fibroblasts are recognized by immunohistochemical analysis by their spindle-shaped appearance and their strong positivity for vimentin stain. Educational Objective: Vimentin stains fibroblasts, a component of connective tissue that is responsible for the early wound healing. References: Goodpaster T, Legesse-Miller A, Hameed MR, et al. An immunohistochemical method for identifying fibroblasts in formalin-fixed, paraffin-embedded tissue. J Histochem Cytochem. 2008;56(4):347-358. First Aid 2014 page 78]]
Approved	Approved::Yes
Keyword	WBRKeyword::Vimentin, WBRKeyword::Stain, WBRKeyword::Immunohistochemical, WBRKeyword::Intermediate filaments, WBRKeyword::Fibroblast, WBRKeyword::Fibroblasts, WBRKeyword::Healing, WBRKeyword::Wound healing, WBRKeyword::Connective tissue
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