# Myoepithelioma of the Hand: A Systematic Review
## 4 Discussion
### Diagnosis  
Accurately diagnosing myoepithelioma in the hand and wrist region involves a combination of imaging techniques and histopathological analysis.  
Initially, radiographs are employed to rule out any bone involvement, providing an initial assessment of adjacent skeletal structures and confirming if the tumor interacts with bone. As described in our results, four authors [13; 14; 17; 20] described a bony myoepithelioma and one author described bony erosion [Figure 3][11].  
Subsequently, ultrasound becomes invaluable for evaluating the soft tissue characteristics of the mass. This technique allows for a detailed examination of superficial structures, aiding in assessing the size, shape, and internal features of the tumor in the hand and wrist [19]. Despite this, only three authors used ultrasound imaging, underlying how the unknown nature of the mass might let the physician ask for a more costly and invasive imaging such as the MRI.  
MRI typically reveals a well-defined mass with a heterogeneous enhancement pattern, providing crucial information for treatment planning and the accurate assessment of the tumor extent in the hand and wrist [35].  
Positron emission tomography (PET) scans have been mentioned in some articles regarding spindle cell myoepithelioma diagnosis; however, their utility may be limited. PET scans could lead to misinterpretation [22], suggesting malignancy when it may not be present, and therefore might be discouraged in favor of more reliable imaging techniques [22].  
For a definitive diagnosis, histopathological analysis following biopsy remains essential.  
This can be achieved through core needle biopsy or excisional biopsy to obtain tissue samples necessary for detailed microscopic evaluation. All authors except for [PERSON], [PERSON] et al. [17] described the excision of the mass without previous needle biopsy.  
Figure 3: X-ray of a 15-year-old patient with a firm mass on his third finger, initially identified as a lipoma. Here, it is the X-ray showing bone erosion of the proximal phalanx [11].  
In one case [11], the previously planned excision was converted into incisional biopsy due to the odd macroscopic aspect during surgery.  
The differential diagnosis includes many entities such as epithelioid schwannoma, epithelioid sarcoma, and, rarely, benign and malignant ossifying fibromyalgiaxoid tumors. Specifically, in the hands, other diagnoses should be ruled out. As emerged from our review, before reaching the final diagnosis, authors suspected ganglion, PVNS [8], lipoma [11], dermatoid cyst [10], and GCT [15]. The ultrasound and MRI features of these neoplasms are almost indistinguishable from those of myoepithelioma. Given the high recurrence rate of some entities, such as GCT [36] and PVNS, accurately diagnosing these conditions is crucial for determining the prognosis (Table 3).  
[PERSON], [PERSON] et al. [22] reported a mass located in the thenar eminence that showed high F-FDG accumulation, leading to the initial suspicion of a malignant lesion. In cases of bony lesions, the first suspicion is usually enchondroma or chondromyxoid fibroma. Finger bony myoepithelioma typically presents as a well-defined, expansive, geographic lytic lesion, which usually does not raise suspicion of malignancy. The first diagnosis can also occur after trauma, as is sometimes seen with enchondromas [20].