Hemangiomas, the most common benign tumor of vascular channels, are of various types, namely, capillary, cavernous, or mixed varieties [1, 2]. Capillary hemangioma occurs in the superficial plane whereas cavernous hemangioma occurs both in superficial and deep planes of the body tissues [3, 4, 5, 6]. Since the pathogenesis of hemangioma is not understood, the management of the tumor remains controversial. Intramuscular hemangioma is a non-malignant, hamartomatous neoplasm that remains unrecognized for a longer period [7, 8]. Intramuscular hemangiomas are usually invasive tumors that manifest in either muscle, bone, or viscera [6, 8]. These hemangiomas may be engorged with blood during activities causing pain and swelling. Lower extremity (45%) hemangioma is more common in occurrence than in the upper extremity (27%) [2, 9]. Superficial skin changes are often not present but they present with calcifications or phleboliths which are diagnostic of cavernous type of hemangioma [3, 4, 10, 11]. Hemangioma of musculotendinous junction of APL and EPB has not been reported yet in literature. We present a case of APL and EPB hemangioma and its management in this case report.

A 15-year-old female presented with the swelling over distal 1/3rd right forearm from the past 5 years, as shown in (Fig. 1). The swelling was insidious in onset and slowly increasing in size. The swelling was associated with mild pain which was non-radiating to the right forearm or arm but localized to the dorsal aspect of distal 1/3rd of the right forearm which was 3 cm away from the articular surface of the right wrist. There was no history of injury, infection, sinus, or other swellings on her forearm. On examination, there was a diffuse, oval-shaped, solitary swelling measuring about 3.5 × 2.5 cm with its surface smooth, edges being indistinct, non-pulsatile, non-fluctuant, non-transilluminant, non-compressible, and non-reducible present over distal 1/3rd of radial side of the dorsal aspect of the right forearm. The swelling was non-adherent to the skin and underlying structures. No muscle wasting was present. There were no arterial bruits and venous hum on auscultation. The distal neurovascular status was intact. Finkelstein’s test was negative, which rule out de Quervain’s tenosynovitis. The range of motions of the right wrist was full and free without any pain. There was no regional lymphadenopathy. A wide range of differential diagnosis of intramuscular lipoma, muscular fibroadenoma, hemangioma, angiofibroma, lymphangioma, neurofibroma, nodular fasciitis, and peripheral nerve sheath tumors was considered.

Plain radiograph of the right wrist revealed a calcified spot in the distal end of the right radius, as shown in (Fig. 2). Ultrasound of the right wrist revealed numerous irregular hypoechoic areas suggestive of low flow vascular tumor. MRI of the right wrist revealed a lobulated lesion (showing T2 and PD/SPAIR hyperintense signals) in the intramuscular plane measuring about 1.8 × 1.2 × 4.2 cm at the radial side in the extensor aspect involving the muscles of abductor pollicis longus and extensor pollicis brevis, as shown in (Fig. 3). Under general anesthesia, an excisional biopsy of the mass, which was arising from the musculotendinous junction of APL and EPB, was done with an uneventful post-operative period, as shown in (Fig. 4). Grossly, it was partially circumscribed soft-tissue mass measuring 5.5 × 2.5 cm. The cut section of the mass showed numerous vessels of variable sizes containing thrombus and hemorrhage. Histopathology of the biopsied muscle revealed an infiltrating tumor composed of variable sized vascular spaces with a predominance of larger sized blood vessels, which are lined by endothelial cells and show RBCs in the lumen. Irregular thin-walled vascular channels were infiltrating within skeletal muscle bundles and fat, as shown in (Fig. 5). The surrounding area showed mature fatty tissues which are suggestive of cavernous hemangioma. The patient has been followed up at regular intervals for 6 months postoperatively during which the patient showed a full range of movements of the thumb. No recurrence was noted during the follow-up period. The patient was still under follow-up.

Hemangiomas contribute to 7% of all soft-tissue tumors, whereas intramuscular hemangiomas are 0.8% of all hemangiomas ^[2]. Hemangiomas are the hamartomatous proliferation of vascular endothelial cells, hyperplastic endothelium, increased cellular mitogenicity, or ectatic blood channels [12, 13]. Hemangiomas are of capillary, cavernous, or mixed variety. Female preponderance (3–5:1) was seen with the hemangiomas and the most common occurrence were reported before the age of 30 years (90%) [2, 14, 15, 16]. Occasionally, hemangiomas were reported in the deeper soft tissues. They express GLUT-1 receptors which are RBC-dependent glucose transporter protein [17, 18, 19]. Intramuscular hemangioma has no relationship with traumatic etiology [10, 20]. Upper extremity hemangiomas (triceps, biceps, FDS, FDP, and pronator quadratus) contribute to 27% of intramuscular hemangioma ^[2]. Kayias et al. reported a case of hemangioma in extensor pollicis brevis with periosteal reaction in radius ^[21]. Histologically, Kayias et al. proposed a classification for intramuscular hemangioma, namely, (a) without periosteal reaction, (b) with periosteal reaction, and (c) with bone and bone marrow involvement ^[21]. No case was reported with the detailed reports of hemangioma in abductor pollicis longus (APL) and extensor pollicis brevis (EPB). Intramuscular hemangioma presents as a slow-growing mass with compressibility and without pulsations or bruits due to the presence of minor vascular malformations [16, 22, 23, 24]. Intramuscular hemangioma poses a major diagnostic challenge [7, 11, 25]. In our case, we found the hemangioma being situated in the flare of musculotendinous portions of APL and EPB without any restrictions of wrist and thumb movements. Radiograph of the right wrist revealed the presence of phleboliths in the distal end of the right radius with soft-tissue swelling. USG of the right wrist showed low flow vascular malformations in the musculotendinous junction of the right APL and EPB. MRI, being the gold standard diagnostic of choice for hemangioma, revealed lobulated lesion (T2 and PD/SPAIR hyperintense signals) in the musculotendinous portion of APL and EPB measuring 1.8 × 1.2 × 4.2 cm at the radial side with few areas of T2 hypointense signals indicating the presence of phleboliths. There was no scalloping effect noticed in the distal end of the right radius. Our case findings are consistent with the reported intramuscular hemangioma. No features of malignancy were observed in the case. The well-defined intramuscular appearance of the hemangioma revealed resectability and hence confirming a benign lesion of vascular origin [2, 7, 10]. Intramuscular hemangioma produces a scalloping effect in the neighboring bone as mentioned by Kumar et al. ^[2] and Ly et al. ^[26]. In our case, we did not observe any scalloping effect or a cortical breach in the neighboring bone. The management of intramuscular hemangioma depends on the tumor location, size, extent, behavior, accessibility, resectability, and cosmetic indications [10, 27]. Depending on the size, the management differ in terms of conservative treatment modalities (spontaneous regression ^[28], interferon-alpha ^[29], imiquimod ^[30], cyclophosphamide [31], and vincristine [32]), minimally invasive methods (radioisotope agents such as strontium-90 [33], sclerotherapy [34], cryotherapy [35], radiation therapy [36], carbon dioxide snow [37], argon laser [38], and Nd:YAG laser [39]), surgical options (ligation of feeding vessels ^[7] and excision biopsy in toto ^[2]), and combination therapy [40, 41, 42, 43, 44, 45]. We instituted excision biopsy in toto to provide a better functional outcome. It is reported that inadequate excision leads to a recurrence rate between 20% and 60% [2, 26, 46, 47]. No recurrence was reported in our case in the past 6 months follow-up. To date, we found a few published pieces of literature on EPB hemangioma which is tabulated in Table 1. One report on APL, EPB, and supinator hemangioma was reported by Yuh et al. but the surgical and prognostic details were found missing in the literature [48]. According to Kayias et al. classification of intramuscular hemangioma, our case belongs to type 1 intramuscular hemangioma without periosteal reaction ^[21].

Being a benign vascular tumor, MRI provides the gateway to diagnose intramuscular hemangioma for early intervention to provide better functional results. The choice of definitive treatment for APL and EPB hemangioma was excision biopsy in toto which provided better functional results in our patient.

Being a benign vascular tumor, MRI provides the gateway to diagnose intramuscular hemangioma for early intervention to provide better functional results.