nerve sheath myxoma ( neurothekeoma ) is an uncommon benign soft tissue tumor of the peripheral nerves with fairly distinctive histological features . a recent immunohistochemical pattern enables a differentiation between myxoid neurothekeoma , melanocytic tumors , and nervous system tumors . we report a rare case of myxoid neurothekeoma in a three - year - old child . a three - year - old boy presented with a nontender , left thumb swelling of four - week duration , without any history of trauma . fine needle aspiration cytology of the mass revealed a few plump - to - oval spindle - shaped cells in a myxoid background . gross examination of the submitted specimen revealed a firm , elastic , tan - colored smooth nodule , measuring 10  8  6 mm with a solid homogeneous gray cut surface [ figure 1 ] . histopathologic examination revealed a nonencapsulated dermal tumor , composed of multiple , closely situated medium - sized nodules with scattered spindle - shaped cells in a myxoid - rich stroma [ figure 2 ] . the tumor exhibited strong positivity for s-100 immunohistochemical stain [ figure 3 ] , and focal positivity for neuron - specific enolase ( nse ) . based on the histopathologic and immunohistochemical results , the case was diagnosed as nerve sheath myxoma of classical type . neurothekeoma : cut section shows solid homogeneous soft , yellowish gray tissue neurothekeoma : tissue section shows a nonencapsulated dermal tumor , composed of multiple , medium - sized nodules composed of few oval - to - plump spindle cells , in a myxoid - rich stroma ( h and e , 10 ) neurothekeoma : the tumor cells show strong positivity for s-100 immunohistochemical stain neurothekeomas commonly present as small solitary erythematous nodules on the face and the upper limb . however , other anatomic sites have been reported in the literature , such as oral cavity , cauda equina , lower limb , shoulder , and neck . it is a tumor of the adolescent and young adult , with a female predilection , but is extremely rare in infancy . neurothekeoma is a rare benign tumor of the nerve sheath , with a distinct histological presentation . it was described initially by hakin and reed , in 1969 , as nerve sheath myxoma but the term neurothekeoma was given by gallager and helwing . there are three histologic variants of neurothekeoma : myxoid ( classical or hypocellular ) , cellular , and mixed type . the myxoid type is characterized by a high degree of myxomatous changes , low cellularity with scattered spindle cells , and is well circumscribed . there may also be multinucleated giant cells and the lesions characteristically stain positively for s-100 , collagen type iv , and nerve growth factor receptor but are negative for epithelial membrane antigen or markers of histiocytic differentiation . in contrast , the cellular types of neurothekeoma are not encapsulated and the mixed type shows areas of varied cellularity with focal myxoid regions . our case is a typical example of a myxoid type of neurothekeoma . the cell of origin of neurothekeoma is controversial with theories proposing a proliferation of schwann cells or other perineural cells . dual immunoreactivity for nse and s-100 protein in a myxoid background supports schwann cell origin , whereas the absence of s-100 protein and positive epithelial membrane antigen in the cellular type suggests perineural cell lineage . fetsch , et al . postulated a tendency of neurothekeoma to recruit histiocytic cells and to differentiate into myofibroblasts . smooth muscle actin ( sma ) positivity suggests some similarity to the epithelioid variant of leiomyoma or myofibroblastic proliferations . glial fibrillary acidic protein ( gfap ) positivity is rare in neurothekeoma ; however , its positivity further supports a peripheral nerve sheath origin , as occasional peripheral nerve sheath tumors may coexpress gfap and s-100 . nerve sheath myxoma and neurothekeoma are recently identified as different entities in gene expression profiling , although they might share some morphologic similarities . gene expression array data strongly supports that nerve sheath myxomas are of peripheral nerve sheath origin and are distinct neoplasms from neurothekeomas . furthermore , data shows many similarities in gene expression between neurothekeomas and cellular fibrous histiocytomas , supporting recent arguments that these entities may in fact be related . there is an overlapping feature with other neural tissue tumors such as schwannoma , nerve sheath myxoma , and neurofibroma , leading to difficulties in diagnosis . differential diagnosis of dermal nodule in infancy and young adulthood should include fibrous tumors , histiocytic tumors , lymphocytic tumors , melanocytic tumors , and neural tumors . reporting such a case will increase awareness about this disease , as it should be included in the differential diagnosis of dermal lesions in young children .