Abstract
Myxoid neurofibroma (MN) is a benign tumor of perineural cell origin, which is demonstrated with a positive immunohistochemical staining for S-100 protein. The most common locations of the MN are the face, shoulders, arms, periungual and in the feet. To our knowledge, this is the first time that a trunk location is reported. MN should be included in the differential diagnosis of tumors on this location.
Keywords: Myxoid neurofibroma, nerve sheath tumor, neurofibroma
Introduction
Neurofibroma can present as a single lesion or be part of a neurofibromatosis.1 Solitary neurofibroma can present as one of the following variants: cutaneous lipomatous, collagenous, epithelioid, granular, pigmented, dendritic cell and myxoid neurofibromas.2
We present the case of a myxoid neurofibroma (MN) of the trunk, which is a rare location of this tumor.
Case Report
A 44-year-old woman presented with a non-tender, slow-growing nodular plaque on the anterior trunk that appeared six years ago (Fig. 1). She sought medical attention for cosmetic reasons.
Fig. 1.
Skin-colored, slow-growing nodular plaque on the anterior trunk
The patient denied any past medical condition or consumption of medication. There were no drug allergic reactions. On physical examination, a 10 × 5-cm flesh-colored plaque on the anterior trunk was observed.
An incisional biopsy was taken. Gross examination shows a well-circumscribed lesion composed of spindle-shaped cells with wavy nuclei (Fig. 2). A few mast cell and mucin were present. Immunohistochemical staining was positive for S-100 protein and negative for CD34. The diagnosis made was myxoid neurofibroma.
Fig. 2.
Numerous spindle-shaped cells with wavy nuclei and mucin (H and E, 40×)
We scheduled a surgical excision that was incomplete and a few months later, a new lesion emerged, a new surgical procedure was programmed but the patient rejected it.
Discussion
Myxoid neurofibroma is a benign tumor of perineural cell origin, which is demonstrated with a positive immunohistochemical staining for S-100 protein.3
This tumor has a higher incidence in young adults.4 It usually presents as a non-tender solitary nodule.3
The most common locations of the MN are the face, shoulders, arms, periungual and in the feet.5,6 To our knowledge, this is the first time that a trunk location has been reported.
MN is usually a solitary lesion,1 as in our patient, however, they can be numerous and may recur following an incomplete initial excision.
Differential diagnosis includes intramuscular myxoma and myxoid dermatofibrosarcoma protuberans. The first one is negative to S-100; and in the second one, on histological examination, slender tumor cells with large, spindle-shaped nuclei are seen, as well as mitotic figures; a high cellularity and irregular, short, intersecting bands of tumor cells forming a storiform pattern are characteristic.7,8
The usual first-line treatment is total excision of tumor,9 but only for cosmetic or diagnostic reasons. Some reports have mentioned the danger of these tumors masquerading as malignancies (mainly neurofibrosarcoma or epithelioid sarcoma).6
To our knowledge, this is the first report of a MN on the trunk. MN should be included in the differential diagnosis of tumors at this location.
Footnotes
Source of Support: Nil
Conflict of Interest: Nil.
References
- 1.Angervall L, Kindblom LG, Haglid K. Dermal nerve sheath myxoma. Cancer. 1984;53:1752–9. doi: 10.1002/1097-0142(19840415)53:8<1752::aid-cncr2820530823>3.0.co;2-2. [DOI] [PubMed] [Google Scholar]
- 2.Mrugala MM, Batchelor TT, Plotkin SR. Peripheral and cranial nerve sheath tumors. Curr Opin Neurol. 2005;18:604–10. doi: 10.1097/01.wco.0000179507.51647.02. [DOI] [PubMed] [Google Scholar]
- 3.Donofrio V, Passeretti U, Russo S. Neurothekeoma of the thumb: A case report. Tumori. 1988;74:751–4. doi: 10.1177/030089168807400622. [DOI] [PubMed] [Google Scholar]
- 4.Rosati L, Fratamico FC, Eusebi V. Cellular neurothekeoma. Appl Pathol. 1986;4:186–91. [PubMed] [Google Scholar]
- 5.King DT, Barr RJ. Bizarre cutaneous neurofibromas. J Cutan Pathol. 1980;7:21–31. doi: 10.1111/j.1600-0560.1980.tb00973.x. [DOI] [PubMed] [Google Scholar]
- 6.Gmyrek RF, Beer R, Silvers DN. Periungual myxoid neurofibroma. Cutis. 2002;69:54–6. [PubMed] [Google Scholar]
- 7.Charron P, Smith J. Intramuscular myxomas: A clinicopathologic study with emphasis on surgical management. Am Surg. 2004;70:1073–7. [PubMed] [Google Scholar]
- 8.Orlandi A, Bianchi L, Spagnoli LG. Myxoid dermatofibrosarcoma protuberans: Morphological, ultrastructural and immunohistochemical features. J Cutan Pathol. 1998;25:386–93. doi: 10.1111/j.1600-0560.1998.tb01763.x. [DOI] [PubMed] [Google Scholar]
- 9.Requena L. Benign neoplasm with neural differentiation. Am J Dermatol. 1995;17:75–96. doi: 10.1097/00000372-199502000-00015. [DOI] [PubMed] [Google Scholar]