Leiomyomas are benign soft tissue tumors that occur wherever smooth muscle is present. They are classified into three groups: cutaneous leiomyomas that arise from the erector pili muscle; vascular leiomyomas that arise from smooth muscle of the vein and leiomyomas of deep soft tissues [3
]. In hand, the tumor is exceedingly rare, it is usually located superficially and in most of the cases is vascular [4
]. Characteristic morphologic features included well-defined circumscription with a fibrous pseudocapsule, myxohyaline stromal degeneration, and intersecting fascicles of spindle cells with mostly uniform, round-ended, elongated nuclei and tapering, eosinophilic cytoplasm [7
Deep soft tissue leiomyomas are uncommon and only sporadic cases have been reported in the literature [1
]. Misumi et al [2
] reviewed 21 cases of deep soft tissue leiomyoma from the English literature and they found to occur at almost any age, ranging from 3 to 62 years (mean, 25 years) and more frequently affected males (14 cases) than females (7 cases). Almost half of the cases were located in the extremities (10 cases), and there was only one report with multiple deep soft tissue leiomyomas [10
The tumor may not be easily recognised until become painful and it is rarely diagnosed before surgery as imaging techniques, including MRI, are not specific for tumor diagnosis [11
]. Lipomas, leioymyosarcomas, schwannoma or neurofibroma, haemangioma, nodular fascitis, soft tissue giant cell tumor such as pigmented villonodular synovitis or giant cell tumor of tendon sheath have to be considered in the differential diagnosis [3
]. Atypical locations of leiomyomas in hand, such as peripheral nerves or tendons may further hamper early and accurate preoperative assessment leading to clinical misdiagnosis and subsequent surgical mismanagement [13
In the herein case, patient symptoms were attributed to idiopathic carpal tunnel syndrome and no further investigation was taken place. Even during the open dissection of the carpal tunnel, no pathology around median nerve was suspected and no meticulous observation of the area was performed. As space occupying lesions were found only in 5.5% of the patients with unilateral carpal tunnel syndrome routine imaging for the investigation of unilateral carpal tunnel syndrome is not essential [14
]. However, the importance of proper clinical and radiologic assessment should not be underestimated as it was clearly dictated in the presented case. We believe that in cases of compression neuropathy in young people, a concern should be raised regarding the presence of an underlying tumor or tumorous condition especially when residual symptoms exist after initial treatment. Furthermore, surgeon should always inspect carpal tunnel and median nerve to rule out any space occupying lesion.
Typically, leiomyoma lacks mitotic activity altogether and the usual treatment is simple excision of the tumor due to its benign character. Billings et al [15
] were reported neither recurrences nor metastases after excision of somatic soft tissue leiomyomas during a mean follow-up of 58.7 months with the longest follow-up being 97 months. This is even more impressive considering that five patients were known to have microscopically positive margins. However, Herren et al [7
] and Neviaser and Newman [8
] described malignant formation of a finger and forearm leiomyoma respectively in which further surgical procedures were required. Despite the rarity of the above phenomenon, these tumors should be approached with caution until histopathologic examination confirms the absence of nuclear atypia, necrosis and mitotic activity.