Does Schwann cell dedifferentiation originate dermal neurofibromas?

Dermal neurofibromas are characteristic of neurofibromatosis type one (NF1), and their developmental origin still unsolved. Although NF1 loss is required for neurofibroma initiation, some features of these benign tumors resemble a skin injury state and cutaneous trauma or other insults might support tumor development. Since adult terminal Schwann cells ensheathing nerve endings are able to dedifferentiate into a progenitor-like state in response to nerve crushing, we hypothesized that dedifferentiation of NF1 Schwann cells could be at the origin of human dermal neurofibromas.

Facial lesions in frontal fibrosing alopecia (FFA): Clinicopathological features in a series of 12 cases.

Background: Facial lesions in frontal fibrosing alopecia (FFA) have been poorly described in published series.

Objective: We sought to describe facial lesions in FFA.

Methods: We reviewed our series of 55 cases of FFA, selecting 12 cases with clinically significant facial lesions.

Association between EGFR gene polymorphisms, skin rash and response to anti-EGFR therapy in metastatic colorectal cancer patients.

Cetuximab and panitumumab are epidermal growth factor receptor (EGFR) inhibitors used in metastatic colorectal cancer (mCRC). Most patients develop a papulopustular rash that may predict tumor response to treatment. EGFR gene polymorphisms may also determine tumor response and appearance of skin rash.

Nevus of striated muscle: a new clinicopathologic entity.

A 3-month-old boy presented with a congenital atrophic plaque on his right palm. On histopathologic examination, bundles of mature striated muscle were noted replacing the subcutis and extending into the dermis, without any other mesenchymal component seen. We have not been able to find a similar previously reported case.

Letter: Photodistributed reticulated hyperpigmentation related to diltiazem.

Diltiazem is a calcium channel blocking agent used for the treatment of hypertension. Cutaneous adverse effects are uncommon. The most frequently reported are itching, urticaria, and maculopapular eruption.