INTRODUCTION
N eurothekeomas are distinctive benign cutaneous tumors of uncertain histogenesis.1 Histologically, neu-
rothekeomas contain proliferating cells arranged in
lobules or fascicles immersed in an amorphous matrix in the
dermis and rarely in subcutaneous tissues.2 Neurothekeomas
were originally described in 1969 by Harkin and Reed, who used
the name “nerve sheath myxoma.”3 The term “neurothekeoma”
was first coined by Gallager and Helwig in 1980 in a study of
distinct benign cutaneous tumors that arose predominantly in
children and adolescents.4 Most of the lesions reported in those
cases were identical to the “nerve sheath myxomas ” previously described by Harkin and Reed,5 which occur in myxoid (classic), cellular and intermediate (mixed) variants.
CASE REPORT
A 45-year-old Saudi male patient without any known chronic
medical illness presented with a nodule on the side wall of the
nose. It started four years ago as an asymptomatic nodule which
progressively increased in size during the first year with no prior
trauma. There was no family history of a similar complaint or of
skin cancer. Drug and allergy histories were unremarkable.
Physical examination revealed a solitary, flat, fir m an d red
nodule with a diameter of 8 mm on the side wall of the nose
(Figure 1). There was no lymph node enlargement. The patient underwent shave diagnostic excision under local anesthesia.
During the excision, it was observed that the deeper part was
coming off easily as lobules; therefore, the entire lesion was
removed by a toothed forceps. No safety margin was included.
The resultant 8 mm diameter defect was closed with a simple
interrupted suture.
Skin histopathology of the lesion showed a dermal lesion consisting of spindle cells with myxoid material in the background.
The cells had thin elongated benign-appearing nuclei arranged
in lobules and surrounded by fibrous tissue (Figure 2). Immunohistochemistry showed positivity for S-100 while smooth
muscle actin and desmin were negative. Based on biopsy and
immunohistochemistry, the diagnosis of a myxoid variant of
neurothekeoma was made. The patient had no recurrence after
three years of follow-up.
DISCUSSION
The origin of neurothekeoma is unknown. Some authors consider Schwann cells to be its origin, while others believe that
perineural tissues or supporting structures of peripheral nerves,
fibroblasts and muscle could be responsible.6 Neurothekeoma
has even been considered a variant of the following dermatoses: dermatofibroma, pilar epithelioid leiomyoma, plexiform
neurofibroma and nerve sheath myxoma.7
