Histopathologic Spectrum of Neuromuscular and Vascular Hamartoma With Special Reference to the Vasculopathic...

Neuromuscular and vascular hamartoma (NMVH) is an unusual lesion presenting as intestinal obstruction by stricture formation. It is characterized by a hamartomatous mass comprising haphazardly arranged mesenchymal tissue native to the intestinal mucosa and submucosa. We aimed to characterize the clinicohistopathological spectrum of NMVH in adult subjects with a search for an etiological clue. We reviewed 84 resected specimens (adult cases) of intestinal obstruction in our institute and diagnosed 4 cases with NMVH. A panel of special stains (Masson trichrome, Verhoeff-van-Gieson, and periodic acid-Schiff) and immunohistochemistry (smooth muscle actin, S100, Bcl₂, CD34, vimentin, desmin, CD117, and CD3) were performed in all cases. All cases of NMVH showed characteristic hamartomatous mounds comprising haphazardly arranged smooth muscle, nerves, ganglia, vessels, and collagen with overlying mucosal ulceration. Adjacent bowel showed submucosal fibrosis, muscularis mucosae thickening, and duplication along with vasculopathy. A typical vasculopathy ("vessel-in-vessel" appearance) was seen in the submucosal and/or subserosal veins. Besides, different other forms of vasculopathic changes like obliterative venopathy and concentric myohypertrophy were also seen. One case had vasculitis and the patient died despite successful surgery. One other case was associated with lymphocytic ganglioneuronitis and granulomatous etiology. We conclude that NMVH can be multifactorial in origin although ischemia resulting from vasculopathy appears to be directly causative. The characteristic vasculopathy in the submucosal location may aid in the diagnosis of NMVH in small biopsy samples.