Dermatology Online Journal

Pachydermodactyly
Raegan Hunt MD PhD, Rajni Mandal MD, Ruth Walters MD, Julie V Schaffer MD
Dermatology Online Journal 16 (11): 5

Department of Dermatology, New York University, New York, New York

---

Abstract

A 16-year-old boy presented to the Pediatric Dermatology Clinic at the Charles C. Harris Skin and Cancer Pavilion with a two-year history of asymptomatic swelling of fingers on both hands. His condition had remained undiagnosed after previous evaluation by several dermatologists and hand specialists. He initially had noticed increased fullness of his proximal left fourth digit. Several months later, he noted swelling of his left fifth digit and right second through fourth digits. The patient reported no pain, pruritus, restriction of movement, morning stiffness, or trauma. He also denied repetitive hand-rubbing movements although his mother stated that he had this habit as a child. Past medical history included allergic rhinitis and asthma. Similar hand findings were not present in any other members of his family.

---

History

Figure 1	Figure 2

Figure 3

Physical examination

There was soft tissue swelling along the radial and ulnar aspects of the proximal interphalangeal joints of the right and (less prominently) left second, third, and fourth fingers; this gave the affected digits a fusiform appearance. Slightly pink, smooth, nodular swelling also was present on the proximal phalanges of the left fourth and fifth fingers. There was no erythema, warmth, or tenderness. All the hand joints had full range of motion without pain, and no joint effusions were evident. The toes were normal.

Laboratory data

The erythrocyte sedimentation rate, C-reactive protein level, thyroid stimulating hormone level, and serum and urine protein electrophoresis were normal. Hand radiographs showed soft tissue swelling but no abnormalities of the joints or bones.

Histopathology

There is epidermal hyperplasia with acanthosis and hyperkeratosis. Collagen fibers in the reticular dermis are thickened and haphazardly arranged, with fibroblast hypercellularity and increased deposits of connective-tissue mucin.

Comment

Originally described by Bazex in 1973, [1] pachydermodactyly is characterized by asymptomatic thickening of the soft tissues that overlie the radial and ulnar aspects of the proximal interphalangeal joints [1, 2]. Fusiform swelling, which typically affects the second through fourth digits and occasionally involves the fifth digit occurs [3, 4]. Skin thickening or nodules sometimes extend to the dorsal aspect of the fingers, and a distal variant also has been identified. No tenderness, warmth, or reduced range of motion of the joints is observed, and radiographs and magnetic resonance imaging show soft tissue thickening but no abnormalities of the joint space or bones [5, 6]. A single case of deforming pachydermodactyly with nonerosive interphalangeal subluxation that resulted in ulnar deviation has been reported [7].

Pachydermodactyly develops most often in healthy adolescents and young adults (median age of 19 years), with a male-to-female ratio of approximately 4:1 [4, 8]. Repetitive mechanical trauma, such as that inflicted by habitual or tic-like hand movement patterns, was noted as a precipitating factor in 35 percent (33/94) of the patients reported to date [8]. In some of these individuals, the ritualistic behaviors were related to sports activities or underlying conditions, such as obsessive-compulsive disorder and Asperger syndrome. Although familial occurrence and association with tuberous sclerosis or Ehlers-Danlos syndrome have been described, pachydermodactyly usually is an isolated, sporadic condition [9, 10].

Histopathologic features of pachydermodactyly include a hyperkeratotic, acanthotic epidermis and a thickened dermis with haphazardly arranged collagen bundles and fibroblasts. Types III and V collagens predominate [11, 12] and electron microscopy has demonstrated increased numbers of thin, collagen fibers [13]. In many cases (including ours), dermal mucin deposition is evident [7]. Although self-healing juvenile cutaneous mucinosis can present with fibromucinous nodules in a periarticular distribution on the hands, fusiform swelling of the lateral digits is not observed, and patients frequently have lesions elsewhere on the body.

Misdiagnosis of the periarticular abnormalities as manifestations of polyarticular juvenile idiopathic arthritis may lead to needless investigations and inappropriate treatment [14, 15]. In pachydermodactyly, patients with repetitive hand movements, appreciable improvement has been observed after cessation of the traumatic activity [16, 17]. Intralesional triamcinolone injections and localized surgical resection also have resulted in reduction of soft tissue swelling in some cases [3, 18].

References

1. Bazex AD, Teillard J. Pachydermie digitale des premieres phalanges par hyperplasie conjonctive dermique et aplasie hypodermique. Bull Soc Fr Dermatol Syphiligr 1973; 80: 455

2. Verbov J. Pachydermodactyly: a variant of the true knuckle pad. Arch Dermatol 1975; 111: 524 [PubMed]

3. Curley RK, et al. Pachydermodactyly: a rare form of digital fibromatosis – report of four cases. Clin Exp Dermatol 1991; 16: 121 [PubMed]

4. Ye S, et al. Pachydermodactyly: six new cases from China. J Clin Rheumatol 2005; 11: 72 [PubMed]

5. Anandacoomarasamy A, et al. Magnetic resonance imaging in pachydermodactyly. J Rheumatol 2005; 32: 2239 [PubMed]

6. Sandobal C, et al. Pachydermodactyly: four additional cases. Clin Rheumatol 2007; 26: 962 [PubMed]

7. Taylor-Gjevre R, et al. A case of deforming pachydermodactyly. J Clin Rheumatol 2009; 15: 78 [PubMed]

8. Beltraminelli H, Itin P. Pachydermodactyly – just a sign of emotional distress. Eur J Dermatol 2009; 19: 5 [PubMed]

9. Russo F, et al. Familial pachydermodactyly. Acta Derm Venereol 1994; 74: 386 [PubMed]

10. Bardazzi F, et al. Pachydermodactyly in two young girls. Pediatr Dermatol 1996; 13: 288 [PubMed]

11. Reichert CM, et al. Pachydermodactyly. Clin Orthop Relat Res 1985; 252 [PubMed]

12. Kang BD, et al. Two cases of pachydermodactyly. Int J Dermatol 1997; 36: 768 [PubMed]

13. Kim TH, et al. Two cases of pachydermodactyly. J Dermatol 1996; 23: 419 [PubMed]

14. Carpentier KG, et al. Pachydermodactyly may mimic juvenile idiopathic arthritis. Clin Exp Rheumatol 2005; 23: 725 [PubMed]

15. Fathalla BM, Goldsmith DP. Pachydermatodactyly mimics polyarticular juvenile idiopathic arthritis. J Pediatr 2009; 155: 931 [PubMed]

16. Lautenschlager S, et al. Pachydermodactyly: reflecting obsessive-compulsive behavior? Arch Dermatol 1994; 130: 387 [PubMed]

17. Iraci S, et al. Pachydermodactyly: a case of an unusual type of reactive digital fibromatosis. Arch Dermatol 1993; 129: 247 [PubMed]

18. Fleeter TB, et al. Pachydermodactyly: a case report and discussion of the pathologic entity. J Hand Surg Am 1984; 9: 764 [PubMed]

© 2010 Dermatology Online Journal