(BMJ)—A 7-yo boy presented w/ a large painless blister on his tongue, which was bifid. He had hx of recurrent traumatic mouth ulcers and tongue trauma, self-extraction of secondary teeth, self-avulsion of finger nails, multiple painless fractures resulting in Charcot joints of the left knee and ankle, mild learning difficulties, and impulsive behavior. Parents are 1st cousins. What is the dx?
Nonaccidental trauma
Melkersson-Rosenthal syndrome
Neurofibromatosis type 1
Behcet syndrome
Hereditary sensory and autonomic neuropathy type 4 (HSAN IV)
You are correct. Hereditary sensory and autonomic neuropathy type 4 (HSAN IV) is a rare autosomal recessive condition that causes problems w/ pain sensation and temperature control. Mutations in the neurotrophic tyrosine receptor kinase 1 (NTRK1) gene result in faulty or deficient neurotrophic tyrosine receptor type 1, which prevents the binding of nerve growth factor and, consequently, the transmission of nerve signals. The affected neurons die prematurely. The sx of HSAN IV result from this premature destruction of sensory nerve cells. This pt’s cousin had a dx of HSAN IV, also known as congenital insensitivity to pain w/ anhidrosis. Genetic testing of this child revealed the same homozygous mutation in the NTRK1 gene as his cousin, confirming the dx.

Archives of Disease in Childhood 2018;103:805
(BMJ)—A 32-yo nulliparous woman presented at 33wk gestation w/ intense pruritus of 1mo duration. There had been no improvement after tx for scabies. Exam: extensive erythematous plaques w/ targetoid lesions, vesicles, and bullae on abdomen, trunk, and all extremities. Labs: mild anemia, LFTs WNL. What is the dx?
Polymorphic urticarial papules and plaques of pregnancy
Dermatitis herpetiformis
Impetigo herpetiformis
Erythema multiforme
Pemphigoid gestationis
You are correct. Serum ELISA and direct immunofluorescence on bx confirmed the dx of pemphigoid gestationis. This is a rare autoimmune dermatosis of pregnancy, and bx is needed to distinguish it from polymorphic urticarial papules and plaques of pregnancy. Pemphigoid gestationis is assoc w/ poor obstetric outcomes, like fetal growth restriction and prematurity. The newborn is affected w/ blisters in 10% of cases. Risk of recurrence in subsequent pregnancies is 5% to 8%. This pt was treated w/ steroids and antihistamines and delivered a baby boy w/ no skin lesions. However, she had a flare-up 3 days postpartum and required 3mo of tx w/ SC goserelin.

BMJ Case Reports 2018;2018:bcr-2018-225242.
(BMJ)—A 26-yo man presented w/ a 7-wk hx of an ulcer on his L elbow that was increasing in size. It had not improved after a course of oral floxacillin. He did not recall any trauma and did not have fever, wt loss, or other lesions. He had been to the Peruvian Amazon 3mo prior. Exam: 2x3-cm ulcer w/ lymphangitis ascending to axilla. What is the dx?
Cutaneous leishmaniasis
Orf
Tropical pyoderma
Pyogenic granuloma
Mycobacterium marinum
You are correct. Punch bx revealed amastigotes of leishmaniasis, which were found to be of the Leishmania viannia complex on PCR testing. This confirmed the dx of new world cutaneous leishmaniasis. This dz is caused by L mexicana complex or L viannia complex (L braziliensis, L guyanensis, or L panamensis). Female sand flies spread the infection, which presents w/ a nodule at the inoculation site. The nodule then ulcerates after a period of weeks, followed by slow healing over a period of months. Treat cutaneous leishmaniasis caused by the L viannia complex w/ parenteral sodium stibogluconate to avoid development of mucocutaneous leishmaniasis. Those returning w/ cutaneous leishmaniasis from North and South America need definitive species typing to guide tx. This pt received IV sodium stibogluconate x20 days, w/ initial resolution of the ulcer. However, it returned after 6mo.

BMJ 2018;362:k3042
(BMJ)—A 17-mo boy had a soft, painless mass in the L eye since birth that gradually increased in size. Exam: mass w/ skin-like surface; the mass covered the cornea and protruded beyond the palpebral fissure. What is the dx?
Corneal dermoid
Staphyloma
Juvenile xanthogranuloma
Foreign body granuloma
Osseocartilaginous choristoma
You are correct. Corneal dermoids are benign congenital choristomas—proliferations of microscopically normal tissue derived from germ cell layers foreign to that site. They frequently locate at the corneal limbus but occasionally involve the entire cornea. The dermoid was excised, and the child underwent lamellar keratoplasty to improve the final appearance. Surgical removal of corneal dermoids at an early age produces better cosmetic results and avoids amblyopia, which is a risk if dermoids involve the visual axis. Systemic examination is recommended to identify possible associated oculoauriculovertebral dysplasia.

BMJ 2018;362:k3200
(BMJ)—A 55-year-old man presented with sudden-onset R-sided weakness and aphasia. A squash ball had hit him in the neck 2 weeks prior. Exam: contusion, L anterior neck; expressive dysphasia; R arm and leg weakness. What’s the dx?
Carotid artery dissection
Vertebral artery dissection
Venous sinus thrombosis
Complicated migraine
Anterior cord syndrome
You are correct. Contrast-enhanced MR angiography confirmed arterial dissection, presumed secondary to neck trauma. Carotid artery dissection accounts for 10% to 25% of ischemic strokes in young patients. Approximately 40% of these dissections are associated with trauma. Embolic events to the brain can occur weeks after the dissection, as in this patient. He was treated with IV thrombolysis. His weakness resolved, and he was left with expressive dysphasia only.

BMJ 2018;362:k3062