Neuromuscular and Vascular Hamartoma of the Small Intestine

Abstract

The term Neuromuscular and Vascular Hamartoma (NMVH) was initially coined by Fernando and McGovern in 1982 in their report of 2 cases. Whether this lesion is truly hamartomatous or represents a "burnt-out" phase of varying chronic pathologies has been debated since that time. Examples of NMVH-like proliferations have been reported in the setting of diaphragm disease, Crohn's disease, radiation, and ischemia. Herein we present the case of a 73-year-old female with partial small bowel obstruction and a past surgical history significant for cholecystectomy and abdominal hysterectomy. A computed tomography scan revealed an ill-defined mass with the same density as muscle extending into the mesentery, worrisome for malignancy and generating the differential of lymphoma versus metastatic disease. Upon laparotomy, a 2.5 cm, constrictive, predominantly mural-based mass was identified. The more proximal bowel was dilated, and there were dense serosal adhesions. Grossly, the transmural lesion had a tan-yellow cobweb-like cut surface and the overlying mucosa was flattened. Histologically, the lesion contained fascicles of smooth muscle, irregularly spaced large nerve bundles, and thick-walled vasculature in a haphazard arrangement within a hypocellular fibroadipose stroma. No stigmata of Crohn's disease were observed, and the uninvolved enteric tissue was unremarkable. The patient's medical history was negative for chronic nonsteroidal anti-inflammatory use and was otherwise unremarkable. This case of an NMVH-like lesion is presented as a reminder of benign mass-forming lesions causing bowel obstruction and suggests that such lesions may develop secondary to a chronic inflammatory process.

Neuromuscular and vascular hamartoma as an unusual cause of small bowel obstruction

“…Similar histological features have been seen in association with a range of chronic reactive conditions, and it has been suggested that the NMVH is not a distinct entity, but is in fact a ‘burnt out’ form of Crohn’s disease or another chronic inflammatory process [2] , [3] , [6] . NMVH-like proliferations have been described in relation to diaphragm disease, radiation enteritis, ischaemic enteritis, and Crohn’s disease.…”

“…However, their cases showed an absence of fissuring ulceration and transmural inflammation, both of which are typical hallmarks of active Crohn’s disease. They suggested that the particular pathological features seen in their four cases may be those of a chronic, ‘burnt out’ form of Crohn’s disease [3] , [6] .…”

“…Occasionally, the transmural inflammation and fissuring which are classically described with Crohn’s disease may be absent, and connective tissue changes (such as fibrosis, muscular hypertrophy, neuronal and vascular changes) represent the only remaining elements of a chronic ‘burnt out’ disease process. It is worth noting that only 5 out of the 23 documented cases of NMVH exhibited prominent fibrosis on histological examination [2] , [3] , suggesting that the remaining 18 cases without significant fibrosis are unlikely to represent a chronic reactive inflammatory condition, or a burnt-out form of Crohn’s disease.…”

“…First described by Fernando and McGovern in 1982, this benign lesion consists of an aberrant proliferation of muscular, neural and vascular elements indigenous to the small intestine [1] . Since its initial description, there have been only 23 cases reported in the English literature [1] , [2] , [3] , [4] , [5] , [6] . NMVH can occur as single or multiple strictures, or single or multiple polypoid-like mass lesions [2] , [3] , affecting a variable length of bowel.…”

“…Since its initial description, there have been only 23 cases reported in the English literature [1] , [2] , [3] , [4] , [5] , [6] . NMVH can occur as single or multiple strictures, or single or multiple polypoid-like mass lesions [2] , [3] , affecting a variable length of bowel. Generally arising from jejunum or ileum, one reported NMVH originated from the caecum [4] .…”