Arteriovenous malformation phenotype resembling congenital hemangioma contains KRAS mutations

Abstract

Extracranial arteriovenous malformation (AVM) is most commonly caused by a somatic mutation in MAP2K1. We report two patients with vascular anomalies that had an unclear clinical diagnosis most consistent with either an AVM or congenital hemangioma. Lesions were cutaneous, reddish-purple with telangiectasias, present at birth, and had defined borders. Histopathology indicated AVM and both lesions contained somatic KRAS mutations. A rare AVM phenotype exists that shares clinical features with congenital hemangioma.

Keywords: KRAS; arteriovenous malformation; congenital; hemangioma.

Figure 1.

(A) Posterior trunk of a 5-year-old male (Patient 1) shows a 6 cm x 4 cm somatic KRAS (Gln22Lys, Gly13Asp) arteriovenous malformation (AVM) with clinical features similar to a congenital hemangioma. (B, C) Histologic examination (hematoxylin and eosin) demonstrates medium to large size channels involving the dermis and subcutaneous tissue [40 X magnification (B), 100 X magnification (C)]. (D) Larger channels show intimal fibromyxoid thickening at 200 X magnification. (E) Posterior neck of a 14-year-old male (Patient 2) illustrates a somatic KRAS (Gly13Arg) AVM with clinical features similar to a congenital hemangioma. (F) MRI demonstrates a T2 hyperintense soft-tissue lesion with multiple flow voids. (G) Angiography shows a pathological capillary blush with nidal-like architecture and tortuosity of feeding arteries. Venous drainage is early, but less significant than a typical AVM. (H, I) Histologic examination (hematoxylin and eosin) demonstrates nodules of small channels, some with capillarous morphology and others with thicker, mostly fibrous walls. Channels are separated by fibrous and adipose tissue [100 X magnification (H), 400 X magnification (I)].