A 32-year-old man comes to the physician for

a follow-up examination 1 month after sustaining a chemical

burn over the dorsum of his right hand and forearm. Physical examination shows

hyperextension of the hand at the wrist. The skin over the dorsum of the wrist

is tense and there is a thick, epithelialized scar. The range of motion of

the right wrist is restricted. Which of the following cell types, with their

increased extracellular matrix production, was most likely responsible for this

contracture?