The diagnosis of FTS is supposed to be confirmed by several aspects such as the patient’s history, the clinical examination, and radiologic and pathologic findings. The major differential diagnosis of superficial type of FTS (Fig. 1) includes plantar fasciitis, plantar fascial fibromatosis and nodular fasciitis. Plantar fasciitis occurs because the supporting plantar fascia of the arch becomes strained and inflamed. The prevalence of plantar fasciitis in the general population is estimated to range from 3.6 to 7 % (Dunn et al. 2004; Hill et al. 2008), is a common problem that affects sport participants as well as inactive middle-aged individuals (Davis et al. 1994; Martin et al. 1998). The patients diagnosed as the superficial type had trauma history commonly. Even if some of them did not have trauma history, the tumor occurring resulted from surface of planta was rubbed frequently. Plantar fascial fibromatosis (Bedogni and Dal Monte 1962; Koudela et al. 2010; Dartoy et al. 1990), also known as Ledderhose’s disease, is a relatively uncommon non-malignant thickening of the feet’s deep connective fascia. At the beginning of the disease, cords and nodules start growing along the plantar fascia. Therefore, that is easy to be confused with FTS. The nodules are slowly growing, most of them are often found in the central and medial portions of the plantar fascia. And at the end of the disease, the cords thicken, the toes stiffen and bend (Barnes et al. 2009). However, the FTS on the surface of plantar cannot influence on the toes. Nodular fasciitis is a benign, fibroproliferative lesion that is thought to represent a reaction to injury or inflammation (Cotter et al. 2000). It most frequently affects the upper extremities, especially the volar aspect of the forearm (Brown and Carty 2005). The characteristic vascular pattern of FTS is not seen in nodular fasciitis microscopically (Hornick and Fletcher 2006). Pathologic examination is the gold standard for diagnosis of FTS, sometimes diagnosis requires immunohistochemical confirmation. Deep type of FTS (Fig. 2) should be differentiated from giant cell tumor of the tendon sheath (GCTTS). These two lesions are similar in size, location, and gross appearance. GCTTS mostly occurs in the toes (Gibbons et al. 2002; Darwish and Haddad 2008). Satti (1992) suggested the pathological study between FTS and GCTTS is difficult to identify. GCTTS may present with bone erosion or destruction in radiography (Uriburu and Levy 1998; Lu et al. 2015). There were infrequent above imaging features in FTS. And there were no giant cells in FTS observed under microscope.
Both Ultrasound and MRI are options for FTS. We choose ultrasound for superficial type of FTS. Ultrasound is an important way with its advantage of noninvasive convenience, also making a more definite diagnosis. Solid soft tissue tumors may be confused with cystic masses on ultrasonography (Lee et al. 2010), so we suggest that using MRI as an additional screening tool. Normally, FTS has a lower signal or slightly higher intensity signal on T2-weighted images. But due to the edema in the tumour or capillary vascularity surrounding tumour reacts high intensity signal on T2-weighted images (Fox et al. 2003). Deep type of FTS especially when neurovascular was involved, MRI play an important role in studying the anatomy, and avoid nerves damage during surgery. The images of tendon and tendon sheath provided effective information for resection range and selecting the most reasonable incision. MRI also would help the clinician finding early recurrence more effectively.
The treatment of FTS is surgical resection. FTS is excised together with the overlying tendon sheath. The indication for surgery is aches and pain. But patients had FTS without any painful discomfort initially also need early resection. Excise to relieve symptoms but preserve function, may be difficult to remove from adherent tendons. Preoperative diagnosis and type are helpful for the design of the operation planning. Superficial type of FTS was easier to remove. But deep type of FTS grows around tendon and joint capsule, especially some patients had neurovascular bundle involved, is difficult to remove from adherent tendons. The tumor cannot be excised completely, which is the main reason to have a recurrence after the surgery. The nerve injury should be avoided during operation. Nerve injury during operation could lead to numbness. Painful scar is also a difficult problem. Light therapy and lasers are meant to minimize its appearance. A malignant transformation has never been described. Only tumour recurrence needs reoperation in follow-up.
