Superficial acral fibromyxoma: Report of two cases and discussion of the nomenclature
1. University of Nottingham, School of Molecular Medicine, Division of pathology, UK
We recently took an extensive review, as part of an audit, of the archives of one of the District General Hospitals in the UK and Jordan University Hospitals, and all lesions coded as myxoma, benign, NOS were retrieved blindly. Approximately 178 cases were reviewed. From these, two lesions of the new entity described by Fetsch et al (2001) with typical clinical, histological, and immunohistochemical were identified and the diagnosis of superficial acral fibromyxoma was made.
Audit has not been properly conducted by trainees in different specialities with a few exceptions. Since audit is an essential part of patient management, we conducted this study which revealed a new entity with a benign course, but with possible recurrences.
Superficial acral fibromyxoma (SAFM) is a distinct clinicopathological entity recently recognized by Fetsch et al. who presented a series of 37 cases in 2001 . Subsequently, a handful of scattered reports describing the typical histological features of SAFM were published [1-8]. The patients in the original description ranged from 14 to 75 years of age and male predominance was observed. The lesions described by Fetsch et al. were mainly observed in the fingers and palms.
We recently took an extensive review, as part of an audit, of the archives of one of the District General Hospitals in the UK and Jordan University Hospitals, and all lesions coded as myxoma, benign, NOS were retrieved blindly. Approximately 178 cases were reviewed. From these, two lesions of the new entity described by Fetsch et al.  with typical clinical, histological, and immunohistochemical were identified and the diagnosis of superficial acral fibromyxoma was made.
They describe the tumor contents as a spindle cell and stellate proliferation embedded in fibromyxoid-collagenous matrix together with increased blood vessels, multinucleated cells and mast cells. The immunophenotype of these lesions was CD34 diffuse or focal positivity, focal EMA positivity, and the presence of CD99, S100, HMB45, cytokeratin, SMA, and desmin.
Two cases were identified. One in a 35 year-old male who had a subungual nodule on his right big toe that was painless and present for 5 years. The second patient was a 45-year-old man who had a slightly pigmented painless mass on his right index finger present for 7 years.
Histologically, the two cases presented as proliferation of spindle or stellate cells with a storiform and fascicular pattern embedded in a myxoid or collagenous matrix, increased number of blood vessels and mast cells in the stroma and a particular immunophenotype. The lesional cells are CD34, CD99 and EMA positive; these cells are negative for cytokeratin, smooth muscle, skeletal muscle and melanocytic markers (Figs. 1-3).
In conclusion, the diagnosis of myxoma, benign, not otherwise specified, should not be used anymore. This tumor, for example is a distinct clinicopathological entity well known to have a recurrence potential. Hence, appropriate diagnosis, complete surgical removal and close follow-up are recommended by the authors.
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