(BMJ)—A 46-yo man presented w/ intermittent pain under his left 4th fingernail x7y. It was worsened by cold weather. Exam: tender, 3-mm round dusky blue lesion under the nail. Bx confirmed dx. What is it?
Venous malformation
Glomus tumor
Pyogenic granuloma
Subungual wart
Cellular blue nevus
You are correct. Bx confirmed a glomus tumor, a rare smooth muscle tumor most common in subungual sites and the fingers and toes. It arises from the glomus body—a thermoregulatory component in the dermis. This dx can be made on hx alone: a subungual lesion w/ pain induced by cold is pathognomonic of glomus tumor. Tx is by excision of the tumor.

BMJ 2016;355:i5149
(BMJ)—A 9-yo boy presented w/ an itchy, nonpainful rash on both feet. He was bitten on the feet by mosquitos 2 days prior. Exam: afebrile. Feet: asymmetrical red streaks. No inguinal adenopathy. What is the dx?
Gnathostomiasis
Superficial thrombophlebitis
Sporotrichosis
Allergic lymphangitis
Cutaneous larva migrans
You are correct. Superficial allergic lymphangitis due to insect bite was diagnosed clinically. The rash cleared w/in 5 days of tx w/ a potent topical steroid. Superficial lymphangitis can occur as an allergic reaction to the mosquito antigen, which is injected into the skin and drained by lymphatic vessels. Infection is not involved.

BMJ 2016;355:i5726