Skeletal Radiol (2005) 34:176–179DOI 10.1007/s00256-004-0817-3 C A S E R E P O R T

Ensar YekelerCandan OzdemirSelman GokalpAbdurrahman YildirimFirdevs BasHulya GunozGulden Acunas

Weismann-Netter-Stuhl syndromein two siblings

Received: 7 March 2004Revised: 17 May 2004Accepted: 18 May 2004Published online: 22 October 2004� ISS 2004

E. Yekeler ()) · C. Ozdemir · G. AcunasDepartment of Radiology,Istanbul University,Istanbul Faculty of Medicine,34390 Capa, Istanbul, Turkeye-mail: ensaryekeler@hotmail.comTel.: +90-212-5337505Fax: +90-212-6310728

S. Gokalp · A. Yildirim · F. Bas · H. GunozDepartment of Pediatric Endocrinology,Istanbul Faculty of Medicine,90 Istanbul, Turkey

Abstract Cases of Weismann-Netter-Stuhl syndrome involving theupper extremities and affecting sib-lings have rarely been reported. Wepresent the radiological findings ofWeismann-Netter-Stuhl syndrome intwo siblings, with upper extremityinvolvement in one of them.

Keywords Weismann-Netter-Stuhlsyndrome · Radiography · Upperextremity

Introduction

Weismann-Netter-Stuhl syndrome is a rare diaphysealdysplasia and was first described in 1954 by Weismann-Netter and Stuhl. Short stature, delayed walking, andsaber shin are important clinical features of the disease[1]. Characteristic roentgenographic findings of the syn-drome are bilateral and symmetrical anterior bowing ofboth tibiae and fibulae with posterior cortical thickening[2]. True tibialization of the fibula, which has been de-scribed as thickening and enlargement of the fibula,confirms the diagnosis [1, 2, 3, 4]. Other occasional bonelesions seen in Weismann-Netter-Stuhl syndrome arefemoral incurvature and exostoses, bilateral coxa vara,bowing of radius and ulna, metacarpal shortening, anddolichophalangy. Kyphoscoliosis and costal deformity,iliac wings, and horizontal sacrum have also been re-ported [2, 3, 4, 5, 6]. Cases involving the upper ex-tremities and affecting siblings have rarely been reportedin this syndrome [3, 4]. In the current two cases, theradiological findings of Weismann-Netter-Stuhl syn-

drome in siblings, with upper extremity involvement inone of them, are presented.

Case reports

Case 1

A 6-year-old boy presented with short stature. On physical exam-ination, in addition to short stature (height 90.2 cm; <3rd percen-tile), anterior and internal convexity of both legs and bowing of theleft radius and ulna were detected (Fig. 1A). Left forearm lengthwas slightly shorter than the right (16.3 cm versus 17 cm). No otherskeletal deformities were present. The parents and other adultmembers of the family had no abnormality of stature. Serum phos-phorus, calcium, and alkaline phosphatase levels, and hydrox-yprolinuria, were in the normal ranges. Serological tests for syphiliswere negative. Thyroid size and echo structure were normal onultrasonography. Roentgenograms including the skull, chest, ver-tebral column, pelvis, and extremities were obtained. Frontal andlateral roentgenograms of the lower extremities showed bilateraland symmetrical anterior and internal bowing of both tibiae andfibulae with posterior cortical thickening. Thickening of both fib-ulae was also detected (Fig. 1B, C). Roentgenograms of the upper

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extremities showed bowing of radius and ulna on the left side. Theroentgenogram of the right arm showed a slightly thickened ulnawith distal shortening (Fig. 1D, E). Roentgenograms of the otherparts of the skeleton were normal.

Case 2

The sibling of case 1, a 3-year-old boy, presented with short stature(height 79 cm; <3rd percentile), and delayed walking. Physicalexamination revealed deformities in both legs (Fig. 2A). Lowerextremity lengths were equal and there was no deformity in theother extremities. Forearm measurements were also equal (15.4 cmfor each). Laboratory and serological data were normal, as in case1. Roentgenograms of the entire skeleton were obtained. Frontalroentgenograms of the lower extremities showed mild internalbowing of the proximal two-thirds of the fibulae and externalbowing of the distal one-third of both tibiae and fibulae (Fig. 2B).Lateral roentgenograms showed marked anterior bowing of bothtibiae and fibulae with slight thickening of both fibulae (Fig. 2C).Roentgenograms of the upper extremities and other parts of theskeleton were normal.

Discussion

Eighty-five cases of Weismann-Netter-Stuhl syndromehave been reported previously, most of which are in theFrench literature. Toxopachyost�ose diaphysaire tibio-p�roniere is the descriptive French term for the syndrome[3]. The disease has been reported mostly in adults, withonly 15 cases in children [2, 7]. Family history has beenuncommonly reported, suggesting genetic transmissionwith incomplete penetration [2, 8]. Siblings are rarelyaffected [4, 8]. Complaints of the affected patients areinsignificant clinically. Most of the subjects reported adelay in ambulation and bowing of the lower extremities.The presence of mild clinical symptoms and unfamiliarradiological features of the syndrome lead to delay in thediagnosis.

Bone involvement in Weismann-Netter-Stuhl syn-drome is frequently bilateral and symmetrical [2, 3, 4, 5,6, 7, 8, 9, 10]. Unilateral involvement is very rare. Inthe literature review by Nores et al. [3], only four of 44cases demonstrated unilateral involvement, only the left

Fig. 1A—E Case 1. A 6-year-old boy with Weismann-Netter-Stuhl syndrome. A Frontal viewshows deformities of both legsand left forearm. B Anteropos-terior radiograph of the legsreveals internal bowing of bothtibiae and fibulae. Notice thatapices of internal bowing ofboth tibiae are located at thejunction of upper one-third andlower two-thirds of the diaphy-sis, in contrast to the classicalsite at the junction of the uppertwo-thirds and lower third. CLateral radiograph revealsthickening of posterior cortices,which have maximum thicknessat the apex of tibial and fibularbowing. Increased diameter ofthe fibula (tibialization) is alsoseen, especially at the lowerone-third. D Roentgenogramsof the left arm show bowing andthickening of the radius andulna. E Roentgenogram of theright arm reveals a thickenedulna with distal shortening

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leg being involved in one case [9] and only the right leg inthree cases [4, 11, 12]. Upper extremities are rarely in-volved and have been reported in only nine cases as bi-lateral [7, 13]. The apex of bowing is classically reportedat the junction of the upper two-thirds and lower third ofthe diaphysis. The apex is located at a slightly higherposition in the tibia than in the fibula [11, 13, 14, 15, 16].Thickening of the posterior cortex is maximum at theapex of tibial and fibular bowing [2, 3, 4, 5, 6, 7, 8, 9, 10].Tibial and fibular bowing are more commonly internal infrontal projection [2, 3, 4, 5, 6, 7, 8, 9, 10]. Increaseddiameter of the fibula (tibialization) is the main feature,and the only feature confirming the diagnosis of thesyndrome [1, 2, 3, 4, 9, 17, 18]. In the current report, theradiographic appearances were characteristic of Weis-mann-Netter-Stuhl syndrome with slight differences be-tween cases 1 and 2 (Figs. 1, 2).

The differential diagnosis of the syndrome with someother disorders such as syphilis, healed rickets, fibrousdysplasia, neurofibromatosis, congenital bowing, and me-somelic dysplasia should be made. Rickets and syphiliscan be excluded by biochemical and serological testing.Characteristic findings of rickets such as epiphyseal andcostal lesions are not seen in Weismann-Netter-Stuhlsyndrome [3]. Rickets is usually bilateral with or withoutmild asymmetrical involvement [3]. In our cases, the di-agnosis of Weismann-Netter-Stuhl syndrome was sug-gested by the presence of anterior bowing of both tibiaeand fibulae with posterior cortical thickening, and normallaboratory data. Healed rickets appears with the followingroentgenographic findings which were not similar to thoseof our cases: metaphyseal lucent bands with adjacentsclerosis, residual bowing of long bones, and “Erlenmeyerflask” metaphyses [19]. Congenital tibial bowing is usu-ally convex posteriorly and medially. The fibula is alsobowed. The foot shows marked dorsiflexion at birth [20].Presence of foot deformity appearing at birth and absenceof tibialization of the fibula in congenital tibial bowingexcludes the diagnosis of Weismann-Netter-Stuhl syn-drome. In neurofibromatosis, there may be anterolateralbowing of the tibia with or without a hypoplastic fibula.Presence of focal narrowing, intramedullary sclerosis orcystic changes at the apex of the angulation, and otherbone lesions, rule out the diagnosis of Weismann-Netter-Stuhl syndrome [20]. Mesomelic dysplasia is character-ized by disproportionate shortness of the middle segmentof the extremities, osteopenia, abnormal trabecular pat-tern, fragile bones, and periosteal thickening due to col-lagen disorder [21]. Severity of limb deformities withshortening differentiates mesomelic dysplasia from Weis-mann-Netter-Stuhl syndrome. But those cases of classicaltibial and fibular involvement with mild upper extremi-ty deformities, which had the diagnosis of Weismann-Netter-Stuhl syndrome, may be a mild form of mesomelicdysplasia. Marked disproportion in extremity lengths andother features of mesomelic dysplasia described abovewere not seen in our cases. Fibrous dysplasia occursmost often in the tibia as a well-circumscribed intracorti-cal lucency, or multiple lucencies separated by scleroticborders, associated with a diaphyseal enlargement. An-terior bowing can be seen in this disorder but bilateralinvolvement is extremely rare. The presence of cysticlesions also excludes the diagnosis of Weismann-Netter-Stuhl syndrome [22].

In conclusion, Weismann-Netter-Stuhl syndrome is arare skeletal disorder which can present at any age andshould be distinguished from other systemic and meta-bolic and dysplastic diseases of bone.

Fig. 2A—C A 3-year-old boy, the sibling of case 1, with Weis-mann-Netter-Stuhl syndrome. A Frontal view shows deformities ofboth legs. B Anteroposterior roentgenogram of the legs revealsmild internal bowing of the proximal two-thirds of the fibulae andexternal bowing of distal one-third of both tibiae and fibulae. CLateral roentgenogram demonstrates marked anterior bowing oftibia and fibula with posterior cortical thickening and tibializationof the fibula

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