WBR0830

Author	[[PageAuthor::Rim Halaby, M.D. [1]]]
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 reveals 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. At this early 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 the extracellular matrix abundant in collagen. Later during the healing process, 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 distinguished under histopathological appearance by their spindle-shaped appearance with positivity to vimentin stain, and absence of positivity to other stains. Educational Objective: Vimentin stains fibroblasts, a component of connective tissue, 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.]]
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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