High-Resolution Ultrasonographic Appearances in Superficial Fibromatoses: Palmar and Plantar Diseases

We have described the characteristic ultrasonographic features using highresolution ultrasonography (US) in palmar fibromatosis or Dupuytrenâ€™s disease...


Introduction
Dermatologic ultrasound imaging has been rapidly growing in recently years [1,2]. Currently, ultrasonography (US) studies for superficial fibromatoses, palmar fibromatosis, namely Dupuytren's disease [3] and plantar disease, namely Ledderhose disease [4] which are located in the subcutaneous tissue have been described in ultrasound field. Dupuytren's disease is a routine for the dermatologist, because patient with subcutaneous nodule may firstly visit a dermatologist. In this review, the author provides an update on the characteristic US appearances in superficial fibromatoses, palmar and plantar diseases.

Dermatological Ultrasound
The international working group, namely DERMUS (Dermatologic Ultrasound) was formed and provided the guidelines [1] and proposed for an assessment training program [2]. Currently, US reports for palmar fibromatosis, namely Dupuytren's disease [3] and plantar disease, namely Ledderhorse disease [4] which are soft tissue tumors have been described in ultrasound field. We usually perform US studies for dermatologic fields with a high-resolution, skin elastic modules values estimated by SWE in healthy individuals are affected mainly by the skin site, sex, and age [19]. Additionally, skin elasticity was higher in men than in women at each site and was increased in subjects aged 20 to 50 years than in the other age group at the finger [19].

Plantar Fascia on Real-Time Tissue Elastography
Sonoelastography study has showed a significantly softer of the plantar fascia in older healthy subjects than in the younger subjects [17,20]. It is suggested that plantar fascia is similar to tendon and the age-related alterations of elasticity may occur in plantar fascia [20]. Plantar fasciitis is a common cause of heel pain. Though the etiology of plantar fasciitis is multifactorial, mechanical overload and degeneration have been considered as the main factors. Grayscale US shows the fascial thickening and hypoechoic echotexture of planar fascia in patients with plantar fasciitis. Softer plantar fascias were shown in patients with plantar fasciitis than in healthy subjects [17,20]. Sconfienza et al. [21] also described that Real-Time Sonoelastography revealed elasticity alterations in symptomatic plantar fasciitis in whom gray-scale US features were inconclusive.

Soft-tissue Masses in Hand Region
Soft-tissue masses have the occurrence forms of characteristic locations. The characteristic location and relation to surrounding structure are very important in the accurate diagnosis [22]. In the cystic tumors, ganglion cyst is the most common masses of the hand and wrist regions. It is mutin filled with a fibrous capsule and occurs in association with a joint or tendon sheath [22]. With regard to the solid tumors, palmar fibromatosis, giant cell tumor of the tendon sheath (GCTTS), and peripheral nerve sheath tumor tend to occur in wrist or hand, while plantar fibromatosis, peripheral nerve sheath tumor and Morton neuroma have tendency of occurrence in ankle or foot region [22]. Superficial fibromatoses in adults (palmar and plantar) and children (calcifying aponeurotic fibroma, lipofibromatosis, and inclusion body fibromatosis) are often small slow-growing lesions and their diagnosis have been suggested by location [23]. In addition to these diseases, fibroma of the tendon sheath (FTS) mostly occurs in fingers, hands, and wrists locations [24].

Clinical Appearances
Dupuytren's disease is a routine for the dermatologist, because patient with subcutaneous nodule may firstly visit a dermatologist.
Kelenjian et al. also suggested that superficial fibromatoses relevant to dermatology include palmar, plantar, and penile fibromatosis, knuckle pads, pachydermodactyly and infantile digital fibromatosis [25]. Palmar fibromatosis was described by the French physician Dupuytren and is referred to as Dupuytren disease [23,26,27].
Dupuytren's disease or palmar fibromatosis characterized by abnormal proliferation of fibroblasts in the palmar fascia and leads to contractures of the fingers. This entity appearing subcutaneous nodule without pain, commonly occur approximately 20% of the people older than 55 years [3]. The fourth and fifth digits may be most commonly affected by palmar fibromatosis. This disease has other types of fibromatosis such as plantar fibromatosis, Peyrone disease, and knuckle pads [23]. Although the etiology of this disease is completely unknown, this entity has the relationship with trauma, microvascular injury, immunologic factors and genetic factors. In addition, palmar fibromatosis is associated with diabetes mellitus, epilepsy, alcoholism, and keloids [23]. Patel et al. [28] suggested that patients with the palmoplantar phenotype of psoriasis were more likely to develop Dupuytren's disease. With regard to the treatment, Eberlein et al. described that therapy of Dupuytren's disease in early stage is necessary and radiation therapy shows an effective and safe threatment [29].

US and MRI Appearances
There have been a few reports on US study [23,30]. Hypoechoic nodules in the palmar subcutaneous tissues, superficial to the flexor tendons [23] or mixed echogenicity [30] were shown on gray-scale US. With respect to color Doppler US findings, the nodule shows hypervascular lesion [23]. MRI appearance show multiple nodular or cordlike, superficial soft-tissue masses arising from the proximal palmar aponeurosis [23]. The corresponding histologic analysis demonstrated that the lesions of low signal intensity with all pulse sequences contained hypocellularity and abundant dense collagen.

Pathological Appearances
Palmar fibromatosis is a very small nodule and it shows a uniform fibroblastic-myofibroblastic proliferation of spindleshaped cells with variably prominent vascularity. The degree of cellularity depends on the age of the lesion. Younger lesions appear as hypercellularity, whereas older ones reveal much less cellularity with more prominent collagen. Moderate mitotic activity without malignancy is shown [25].

Clinical Appearances
It has been reported that concomitant palmar fibromatosis occurs in 10%-65% of patient with plantar disease. Plantar fibromatosis is a benign fibroproliferative disorder of the plantar fascia described by Georg Ledderhose [4]. This entity appears as a palapable mass in the midfoot or forefoot region. Plantar fibromatosis was shown as a firm subcutaneous nodule. Similar to palmar fibromatosis, plantar fibromatosis is also associated with diabetes mellitus, epilepsy, keloid and alcoholism. Pathologically, the features of plantar fibromatosis is identical to that of palmar fibromatosis. Family studies have revealed that there is a genetic component with manifestation of palmar and plantar fibromatosis. has been revealed as a potential risk factor in fibrotic disease [32]. They suggest that ASTE1 may contribute to the increased risk for palmar/plantar fibromatosis in patient with Lamin A/C haploinsufficiency [32].

US and MRI Apearances
Plantar lesions appear similar to palmar type on gray-scale US. The well-defined or fusiform lesion with hypoechoic or mixed echogenic were depicted in the subcutaneous layer superficial to the plantar aponeurosis [23]. Color Doppler US demonstrate hypervascularity lesion in most cases [23]. Cohen et al. [4] described a novel appearance termed the "comb sign" on grayscale US. They also mentioned that plantar fibromatosis shows mixed echogenicity and posterior echo enhancement on grayscale US. Approximately half cases show internal vascularity in the nodule on color Doppler US. With regard to MRI features, the lesion demonstrates predominantly low to intermediate signal intensity on T1-weighted and T2-weighted images. It is indicated that the termed "fascial tail sign "along the plantar aponeurosis are common and seen on enhanced MRI image [23,26].

Giant Cell Tumor of the Tendon Sheath
As similar to palmar fibromatosis, giant cell tumors of the tendon sheath (GCTTS) commonly occurs in the volar aspect of the finger. Tthereby, it is important to distinguish palmar fibromatosis from GCTTS. GCTTS is a type of benign soft tissue tumor that was first described by Chassaignac [33,34]. The World Health Organization distinguishes between two types, namely localized and diffuse forms of of GCTTS originating from the tendon and the synovium [34,35]. GCTTS is also termed tenosynovial giant cell tumor. Clinically, the localized type occurs most frequently in the hand, especially in the volar aspect of the first three fingers [36]. The author suggests that clinical manifestation of palmar fibromatosis appears at the fouth or fifth digits, while GCTTS occurs at the first three digits. With dynamic information, GCTTS do not move with flexion and extension of the digits. Because they arise from the tendon sheath and not the tendon [22]. Histologic examination of GCTTS classically shows a lobulated, circumscribed, cellular tumor [37]. GCTTS consists of three cell types, namely, multinucleated osteoclastlike giant cells, round or polygonal mononuclear cells and foam cells or histiocytes [38]. Wan et al. [39] reviewed imaging of GCTTS and suggested that US showed a soft mass related to the tendon sheath on gray-cale US. They represent hypervascular lesion on color or power Doppler US. With regard to MRI imaging, the lesion typically shows low to intermediate signal on T1-and T2-weighted spin-echo sequencies due to the hemosiderin [39]. Middleton et al. [40] described that this entity al. [41] described that this disease appears as hypoechoc nodule on gray-scale US. Substantial flow could be seen in most lesions [41]. Ansari et al. mentioned that a well-defined hypoechoic mass was depicted on gray-scale US [42]. It is suggested that GCTTS typically exhibits a low signal intensity on T1 and T2 weighted images due to the presence of hemosiderin [34]. On MRI appearances, GCTTS appears as a focal mass, often adjacent to or surrounding a tendon.

They usually show intermediate or low signal intensity on T1 and
T2 weighted images and are well enhanced with contrast medium administration [43][44][45].

In Summary
It is putative that palmar fibromatosis shows hypoechoic nodule which is located in the subcutaneous tissue on gray-scale US.
It is plausible that plantar fibromatosis shows mixed echogenicity on gray-scale US and tends to represents vascular flow on color Doppler US. It is suggested that GCTTS shows hypoechoic nodule with vascularity on US study and represents low signal intensity on T1 and T2 weighted MR images due to the hemosiderin.

c)
Clinically and genetically, it may be important that Ledderhose disease shoud be considered as a concomitant disease of Dupuytren's disease.

Acknowledgement
The author appreciates Dr. Minoru Oishi and Dr. Ken Hayashi for their kind support.