A superficial acral fibromyxoma is a type of

myxoma A myxoma (New Latin from Ancient Greek, Greek 'mucus') is a myxoid tumor of primitive connective tissue. It is most commonly found in the heart (and is the most common primary tumor of the heart in adults) but can also occur in other locations ...

and is a rare cutaneous condition characterized by a

mesenchymal Mesenchyme () is a type of loosely organized animal embryonic connective tissue of undifferentiated cells that give rise to most tissues, such as skin, blood, or bone. The interactions between mesenchyme and epithelium help to form nearly ever ...

neoplasm that typically occurs on the digits of middle-aged adults.

Signs and symptoms

Superficial acral fibromyxoma impacts the palm, heel, and ankle in addition to the acral regions, with a clear preference for the periungual and subungual regions of the fingers and toes. It begins as a slow-growing, solitary

nodule Nodule may refer to: * Nodule (geology), a small rock or mineral cluster * Manganese nodule, a metallic concretion found on the seafloor *Nodule (medicine), a small aggregation of cells *Root nodule Root nodules are found on the roots of plants, ...

limited to the

dermis The dermis or corium is a layer of skin between the epidermis (skin), epidermis (with which it makes up the cutis (anatomy), cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from s ...

and

subcutaneous tissue The subcutaneous tissue (), also called the hypodermis, hypoderm (), subcutis, or superficial fascia, is the lowermost layer of the integumentary system in vertebrates. The types of cells found in the layer are fibroblasts, adipose cells, and ma ...

, and it is typically painless. They range in size from 0.6-5 cm. Fifty percent of the cases involve the nails, exhibiting either

onycholysis Onycholysis is a common medical condition characterized by the painless detachment of the nail from the nail bed, usually starting at the tip and/or sides. On the hands, it occurs particularly on the ring finger but can occur on any of the finger ...

hyperkeratosis Hyperkeratosis is thickening of the stratum corneum (the outermost layer of the epidermis, or skin), often associated with the presence of an abnormal quantity of keratin,Kumar, Vinay; Fausto, Nelso; Abbas, Abul (2004) ''Robbins & Cotran Pathol ...

Causes

Although a precise cause has not been identified, history of trauma is uncommon and has been documented.

Diagnosis

A histologic examination reveals stellate and spindled

fibroblast A fibroblast is a type of cell (biology), biological cell typically with a spindle shape that synthesizes the extracellular matrix and collagen, produces the structural framework (Stroma (tissue), stroma) for animal Tissue (biology), tissues, and ...

-like cells proliferating moderately within a myxoid and/or collagenous matrix with prominent microvasculature. There may be a

hyperkeratotic Hyperkeratosis is thickening of the stratum corneum (the outermost layer of the Epidermis (skin), epidermis, or skin), often associated with the presence of an abnormal quantity of keratin,Kumar, Vinay; Fausto, Nelso; Abbas, Abul (2004) ''Robbins ...

overlaying

epidermis The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and Subcutaneous tissue, hypodermis. The epidermal layer provides a barrier to infection from environmental pathogens and regulates the ...

. The tumor cells are distributed in a focally fascicular and loose storiform pattern. This tumor can be positively stained with

CD34 CD34 is a transmembrane phosphoglycoprotein protein encoded by the CD34 gene in humans, mice, rats and other species. CD34 derives its name from the cluster of differentiation protocol that identifies cell surface antigens. CD34 was first desc ...

CD99 CD99 antigen (Cluster of differentiation 99), also known as MIC2 or single-chain type-1 glycoprotein, is a heavily O-glycosylated transmembrane protein that is encoded by the ''CD99'' gene in humans. The protein has a mass of 32 kD. Unusually fo ...

vimentin Vimentin is a structural protein that in humans is encoded by the ''VIM'' gene. Its name comes from the Latin ''vimentum'' which refers to an array of flexible rods. Vimentin is a Intermediate filament#Type III, type III intermediate filamen ...

, and

CD10 Neprilysin (; also known as membrane metallo-endopeptidase (MME), neutral endopeptidase (NEP), cluster of differentiation 10 (CD10) and common acute lymphoblastic leukemia antigen (CALLA)) is an enzyme that in humans is encoded by the ''MME'' ge ...

. Differential diagnosis includes periungual and subungual

fibroma Fibromas are benign tumors that are composed of fibrous or connective tissue. They can grow in all organs, arising from mesenchyme tissue. The term "fibroblastic" or "fibromatous" is used to describe tumors of the fibrous connective tissue. Wh ...

, acquired digital fibrokeratoma, superficial angiomyxoma, myxoid

neurofibroma A neurofibroma is a benign nerve-sheath tumor in the peripheral nervous system. In 90% of cases, they are found as stand-alone tumors (solitary neurofibroma, solitary nerve sheath tumor or sporadic neurofibroma), while the remainder are found in ...

, dermal mucinosis, sclerosing perineuroma, low grade fibromyxoid sarcoma, myxoid

dermatofibrosarcoma protuberans Dermatofibrosarcoma protuberans (DFSP) is a rare locally aggressive malignant cutaneous soft-tissue sarcoma. DFSP develops in the connective tissue cells in the middle layer of the skin (dermis). Estimates of the overall occurrence of DFSP in the U ...

, fibroma of tendon sheath, giant cell tumour, glomus tumour, fibrous histiocytoma, cutaneous myxoma and inflammatory myxohyaline tumour of distal extremities.

Treatment

Complete excision, which typically prevents recurrence, and regular follow-up are recommended surgical therapy techniques.

Outlook

Superficial acral fibromyxoma has a benign course. Though it is possible for the tumor to convert into a low-grade malignant tumor, no malignant transition has been documented till 2001. There have been reports of 22–24% local recurrence rates.

Epidemiology

The majority of affected individuals are young adults (mean age: 46 years), with a 2:1 male to female ratio.

References

External links

DermNet

{{Soft tissue tumors and sarcomas Dermal and subcutaneous growths