Abbreviations

M.R.I – Magnetic Resonance Imaging.
Tc – Technetium.
F.N.A.C – Fine Needle Aspiration Cytology.
C.T – Computed Tomography.
m/s- Meters per second.
Fig – Figure.
cm – centimeter.

Introduction

Intramuscular haemangioma is a rare vascular tumor and accounts for less than 1% of all haemangiomas₁,₂. It commonly involves the extremity muscles, while only three cases of abdominal wall muscle haemangioma are reported in English literature₁. Inspite of its rarity these haemangiomas are of clinical interest because of their varied clinical presentations and ability to mimic aggressive tumors.

Case Note

A 17 year old boy presented to us with a lump in his left side of abdomen which he had observed at 5years age. He was operated upon outside once for the lump three months back which was aborted midway due to excessive hemorrhage. Lump has since gradually increased to the present size. On examination there was a scar over the mass, but no impulse on coughing, visible peristalsis or skin discoloration seen. It was soft in consistency, compressible and non pulsatile about 7X4 cm in size occupying the left side of umbilical and hypogastric region. On leg raising test the swelling became prominent. His routine investigations were within normal limits. Fine needle aspiration cytology picture was inconclusive which showed a bloody picture with some skeletal muscle cells. Doppler study showed the mass lesion in the left side of anterior abdominal wall in the left rectus muscle with sinusoidal channels typical of a haemangioma. A feeding vessel was arising from the left inferior epigastric artery with increased flow rate in the left artery compared with the right inferior epigastric artery. [Fig 1].

Figure 1

Figure 1: Doppler sonography showing mass lesion in left rectus muscle with increased flow in left inferior epigastric (357m/s) compared to right (271m/s).

The patient underwent surgery and the whole mass with the involved left rectus muscle was excised. [Fig 2]

Figure 2

Figure 2: Excised muscle and haemangiomatous tissue.

The left inferior epigastric vessel was ligated and divided. Anterior abdominal wall defect was repaired with a single layer of Polypropylene mesh. Post operative histopathology showed large, thin walled dilated vessels lined by flattened endothelial cells characteristic of cavernous haemangioma. [Fig 3]

Figure 3

Figure 3: Histopathology picture showing thin walled dilated vessels with flattened endothelial cells.

The patient is well and diseases free at 18 months follow up.

Discussion

Vascular malformations are benign and rare tumors which generally present during the early years of life₁. They are of interest due to their ability to mimic malignant tumors and varied presentations₃. It usually is a slow growing mass that may or may not be painful₃. Intramuscular haemangioma is a rare entity accounting for less than 1% of all haemangiomas₁,₂. Mostly they occur in limbs followed by the head and neck region1. Abdominal wall muscle is the rarest site among all intramuscular haemangioma with probably only three previously reported cases₁.

The exact cause of intramuscular haemangioma has been something of an enigma₃. Theories of congenital developmental anomaly along with preceding history of trauma have been listed as major factors3. Abdominal wall muscle could be an infrequent site for vascular malformation due to less chance of trauma compared to the limbs and absence of any direct high flow arterial branch supplying the muscles. Soft tissue swelling and pain are common symptoms for intramuscular haemangiomas₃,₄. Pain has been attributed to the peculiar association of abnormal blood vessels with nerve fibres and presence of substance P in substantial levels₃. These tumors also can mimic aggressive tumors like sarcomas₁,₅.

Clinically haemangiomas can be misdiagnosed in 90% of cases₃. Diagnostic approaches with Doppler imaging, Magnetic Resonance Imaging (MRI), Angiography and Tc-99m erythrocyte localization give significantly better results₁,₂,₆,₇. MRI has been used as a diagnostic modality in all three previously reported cases of abdominal wall haemangioma and is perhaps the modality of choice to know the extent of the tumor1. Doppler sonograrphy like in our case has also been reported as a useful procedure in describing arteries around the masseter muscle₈. Based on the predominant vascular pattern they are classified histologically into three types, capillary, cavernous and mixed types₃.

Treatments of these tumors have evolved over the time. Spontaneous resolution has been known to occur₃. Conflicting reports of radiotherapy, cryotherapy and angio-embolization are reported in literature₃,₆. Surgical excision of the mass and the involved muscle with ligation of the identified feeding vessel is probably the choice of treatment in all intramuscular haemangiomas including abdominal wall haemangiomas₁,₃,₉. Abdominal wall haemangiomas need special precaution in closing the defect caused by the excised muscle₁. Rarity of the tumor with lack of large series and definitive management protocol has shown a high incidence of recurrence and worsening of symptoms, which is directly related to failure in identification of feeding and draining vessels₁.

Figure 4

Table 1: Table showing characteristics of previously reported abdominal wall haemangioma and the present case.

Conclusion

Abdominal wall intramuscular haemangioma is a very rare type of vascular tumor probably due to anatomical factors of the supplying vessels. It needs a high index of suspicion, to diagnose pre-operatively. Doppler sonography can be used to delineate the feeding vessels and surgical excision of the mass remains the best modality of treatment.

Correspondence to

Prof. V. K. Shukla, M.Ch.(Wales) Professor and Head Department of General Surgery Institute of Medical Sciences Banaras Hindu University Varanasi – 221005, INDIA E-mail: vkshuklabhu@gmail.com Tel.No.: 0091 542 2307507 Fax No.: 0091 542 2367568