Presentation and treatment of macrodactyly in children

Megadactyly with syndactyly of the right toes, a rare case report

INTRODUCTION AND IMPORTANCE

Megadactyly of the foot is uncommon non hereditary congenital anomalies of the extremities and poses a dilemma on treatment however multiple treatment modalities were developed but is not uniform to all patients with megadactyly. The goal of the surgical treatment is to achieve painless and function of the foot.

CASE PRESENTATION

We report a 14 years old male presented with complaints of progressive enlargement 2nd, 3rd, 4th and 5th toes of the right foot since birth, associated with inability to wear shoes. One month prior to admission he experienced gradual onset painful forefoot and toes that was increasing in severity with time associated with inability to walk normally. He is the first born in a family of four children and his other siblings are healthy with no anomalies. On clinical evaluation, he was health with stable vitals, with enlarged 2nd, 3rd, 4th and 5th toes of the right foot with no tenderness with intact neurovascular status. On clinical and radiological evaluation he was diagnosed with congenital megadactyly of the right foot, a multidisciplinary team including orthopedic surgeons and prosthetics team agreed to do trans-metatarsal, then partial foot prosthesis fabrication. He underwent trans-metatarsal amputation of the affected foot and tissue sample was taken for histopathology. The histological findings revealed bone enlargement with increased proliferation of subcutaneous adipose tissues with increased fibrous septae together with thinning of the epidermis, features suggestive of lipomatosis. The wound site healed very well after 14 days stitches were removed and the child was scheduled for follow-up after six weeks, 12 weeks and 6 month post-surgery. On the last visit he was free from pain on his right forefoot and toes, able to wear fabricated partial foot prosthesis and shoes normally, walk with no incapacitation.

DISCUSSION

Our case report is unique due to the involvement of the multiple toes of the right foot with syndactyly at third and fourth toes and its management is challenging because there is no uniformity in its surgical treatment, in our case trans-metatarsal amputation was done and the patient progressed well after six months of follow up.

CONCLUSION

Foot megadactyly is uncommon congenital malformation, most common on the right foot. Regardless of the dilemma on treatment, the trans-metatarsal amputation and a fabricated prosthesis to our patient fulfilled the goals of painless right foot and able to wear shoes and walk normally with no impairment.

Innovative Reconstructive Management of Foot Macrodactyly in a Pediatric Patient: A Case Report

Macrodactyly is a rare congenital anomaly characterized by disproportionate hypertrophy of one or more digits or the forefoot, involving some or all tissue types. It is nonhereditary and can present alone or alongside other deformities. Usually, macrodactyly is treated with amputation of the affected toe or finger to reduce the chance of recurrence. In this paper, we present the case of a child with macrodactyly who was treated successfully without amputation and instead with a reconstruction of the toe shape to resemble a near-natural-looking toe with intact functions. The patient was a one-year-old female who presented with macrodactyly of her right great toe, right second toe, and forefoot. She had no history of other congenital deformities or systemic diseases. A reconstruction surgery was performed, which involved debulking the right great toe, right second toe, and forefoot. Also, it included the creation of the first web space and the restoration of the nailbed of the second toe. Postoperative follow-up revealed minimal complications. Thus, a second reconstructive surgery was performed, which included debulking and further reconstruction of the foot to improve the result. Several techniques exist for the reduction of macrodactyly that can achieve optimal results. The choice of technique depends on the specifics of the case and the experience of the surgeon. We therefore hope our technique will be beneficial for the management of future cases of macrodactyly. One year of follow-up after the second operation revealed maintained function and no regrowth recurrence.

PIK3CA-related overgrowth spectrum (PROS) presenting as isolated macrodactyly

PIK3CA-related overgrowth spectrum (PROS) is a heterogeneous group of diseases, with varied clinical presentations ranging from isolated segmental overgrowths to megalencephaly and vascular malformations, all resulting from post-zygotic activating mutations in PIK3CA. Isolated macrodactyly of upper limb is extremely rare, accounting only for 0.9%-1% of all congenital anomalies of the upper limb. This report describes a case of congenital, isolated, nonprogressive macrodactyly of the right index finger and thumb, in an adult patient that was treated with debulking surgery. The microscopic features were compatible with lipomatosis of nerve. Due to the prompt and pertinent molecular testing, which identified a somatic PIK3CA variant, c.3140A > G, p.H1047R., the case was classified as a PROS. The availability of mTOR inhibitors offers additional treatment possibilities in cases with progressive disease. This case report highlights the importance of molecular testing to identify PROS, to further the knowledge of this continually expanding entity.

The Effect of Epiphysiodesis on the Longitudinal Bone Growth of Hands or Feet in Children With Macrodactyly Based on Long-term Quantitative Analysis

BACKGROUND

Treatment protocols for macrodactyly have not been elucidated due to its rarity and variety of clinical manifestations. This study aims to share our long-term clinical results of epiphysiodesis in children with macrodactyly.

METHODS

A retrospective chart review was performed for 17 patients with isolated macrodactyly treated with epiphysiodesis over 20 years. Length and width of each phalanx in both the affected finger and the corresponding unaffected finger in the contralateral hand were measured. Results were presented in ratios of the affected to unaffected side for each phalanx. Measuring of length and width of phalanx was performed preoperatively and postoperatively at 6, 12, and 24 months, and the last follow-up session. Postoperative satisfaction scoring was done with visual analogue scale.

RESULTS

The mean follow-up period was 7 years and 2 months. In the proximal phalanx, length ratio significantly decreased compared with preoperative state at after more than 24 months, in the middle phalanx after 6 months, in the distal phalanx after 12 months. When classified by the growth patterns, the progressive type showed significant decrease in length ratio at after 6 months, and the static type after 12 months. Patients were overall satisfied with the results.

CONCLUSION

Epiphysiodesis effectively regulated longitudinal growth with different degree of control for different phalanges in the long-term follow-up.

Localized heterochrony integrates overgrowth potential of oncogenic clones

Somatic mutations occur frequently and can arise during embryogenesis, resulting in the formation of a patchwork of mutant clones. Such mosaicism has been implicated in a broad range of developmental anomalies; however, their etiology is poorly understood. Patients carrying a common somatic oncogenic mutation in either PIK3CA or AKT1 can present with disproportionally large digits or limbs. How mutant clones, carrying an oncogenic mutation that often drives unchecked proliferation, can lead to controlled and coordinated overgrowth is unknown. We use zebrafish to explore the growth dynamics of oncogenic clones during development. Here, in a subset of clones, we observed a local increase in proportion of the fin skeleton closely resembling overgrowth phenotypes in patients. We unravel the cellular and developmental mechanisms of these overgrowths, and pinpoint the cell type and timing of clonal expansion. Coordinated overgrowth is associated with rapid clone expansion during early pre-chondrogenic phase of bone development, inducing a heterochronic shift that drives the change in bone size. Our study details how development integrates and translates growth potential of oncogenic clones, thereby shaping the phenotypic consequences of somatic mutations.

The long-term progression of macrodactyly

BACKGROUND

Macrodactyly is a rare congenital disorder of overgrowth affecting the digits of the upper or lower extremity. Mostly, patients are surgically treated during childhood to reduce the digit or to stop growth. There are no standardized guidelines for the treatment and follow-up of macrodactyly. Consequently, follow-up may not be regularly scheduled into adulthood.

METHODS

A retrospective, descriptive analysis of patients with the long-term progression of macrodactyly who presented at our tertiary referral hospital between July 2018 and March 2020 was performed. All patients from our local macrodactyly database were screened for progression of macrodactyly since adulthood; this resulted in four patients. The aim of these case series is to highlight the clinical features and disease course at long-term follow-up.

RESULTS

All patients were surgically treated during childhood and showed progression of tissue overgrowth during adult life. All patients developed severe secondary degenerative bone changes in macrodactyly affected digits, such as ankyloses of joints, new bone formation, and bony spurs. Subsequently, tissue overgrowth and degenerative bone changes led to functional problems.

CONCLUSION

Patients with macrodactyly may experience growth during adult life, which may progress to deforming changes. Consequently, patients should be informed about the possible growth, and the progressive growth should be monitored.

An Analysis of the Pathogenic Genes and Mutation Sites of Macrodactyly

Objective

This study aimed to explore the pathogenic genes and mutation sites of macrodactyly.

Methods

Whole-exome sequencing was performed on the pathological tissue and peripheral blood of 12 patients with macrodactyly who were operated in our hospital between June 2018 and May 2020. In order to conduct comprehensive bioinformatics analysis and screen the pathogenic genes of macrodactyly, the patients were divided into four groups: macrodactyly of finger group, macrodactyly of foot group, macrodactyly and syndactyly of finger group, and macrodactyly and syndactyly of foot group. The results of the whole-exome sequencing were verified using Sanger sequencing in order to clarify the pathogenic genes and mutation sites of macrodactyly, and immunohistochemical analysis of the protein signaling pathways encoded by the pathogenic genes was performed to observe the protein expression and further verify the mutant genes.

Results

In the comprehensive bioinformatics analysis and Sanger verification of the whole-exome sequencing, the PIK3CA gene mutation was screened as the pathogenic gene of macrodactyly. The mutation sites were identified as the p.E542K (c.G1624A) and p.E545K (c.G1633A) sites of exon10 and the p.H1047R (c.A3140G) and p.G1049R (c.G3145C) sites of exon21. Among these, the p.G1049R (c.G3145C) locus was found in macrodactyly for the first time. The mutation of the PIK3CA gene was also found to lead to increased expression of serine-threonine kinase (AKT) in adipocytes in the PI3K-AKT-mTOR signaling pathway.

Conclusion

Mutation of the PIK3CA gene leads to the enhancement of the PI3K-AKT-mTOR signaling pathway, which is the cause of macrodactyly. There is also some diversity in PIK3CA gene mutation sites.

Neural control of growth and size in the axolotl limb regenerate

The mechanisms that regulate growth and size of the regenerating limb in tetrapods such as the Mexican axolotl are unknown. Upon the completion of the developmental stages of regeneration, when the regenerative organ known as the blastema completes patterning and differentiation, the limb regenerate is proportionally small in size. It then undergoes a phase of regeneration that we have called the ‘tiny-limb’ stage, which is defined by rapid growth until the regenerate reaches the proportionally appropriate size. In the current study we have characterized this growth and have found that signaling from the limb nerves is required for its maintenance. Using the regenerative assay known as the accessory limb model (ALM), we have found that growth and size of the limb positively correlates with nerve abundance. We have additionally developed a new regenerative assay called the neural modified-ALM (NM-ALM), which decouples the source of the nerves from the regenerating host environment. Using the NM-ALM we discovered that non-neural extrinsic factors from differently sized host animals do not play a prominent role in determining the size of the regenerating limb. We have also discovered that the regulation of limb size is not autonomously regulated by the limb nerves. Together, these observations show that the limb nerves provide essential cues to regulate ontogenetic allometric growth and the final size of the regenerating limb.

Humans’ ability to regrow lost or damaged body parts is relatively limited, but some animals, such as the axolotl (a Mexican salamander), can regenerate complex body parts, like legs, many times over their lives. Studying regeneration in these animals could help researchers enhance humans’ abilities to heal. One way to do this is using the Accessory Limb Model (ALM), where scientists wound an axolotl’s leg, and study the additional leg that grows from the wound.

The first stage of limb regeneration creates a new leg that has the right structure and shape. The new leg is very small so the next phase involves growing the leg until its size matches the rest of the animal. This phase must be controlled so that the limb stops growing when it reaches the right size, but how this regulation works is unclear. Previous research suggests that the number of nerves in the new leg could be important.

Wells et al. used a ALM to study how the size of regenerating limbs is controlled. They found that changing the number of nerves connected to the new leg altered its size, with more nerves leading to a larger leg. Next, Wells et al. created a system that used transplanted nerve bundles of different sizes to grow new legs in different sized axolotls. This showed that the size of the resulting leg is controlled by the number of nerves connecting it to the CNS. Wells et al. also showed that nerves can only control regeneration if they remain connected to the central nervous system.

These results explain how size is controlled during limb regeneration in axolotls, highlighting the fact that regrowth is directly controlled by the number of nerves connected to a regenerating leg. Much more work is needed to reveal the details of this process and the signals nerves use to control growth. It will also be important to determine whether this control system is exclusive to axolotls, or whether other animals also use it.

Strategy and clinical outcomes of child foot surgery for macrodactyly

BACKGROUND

Amputation of the abnormal segment seems to be the reference standard treatment for the surgical management of macrodactyly of the foot in children. Our objectives here were to detail the surgical strategies according to the cause, anatomical characteristics, and static or progressive nature of the macrodactyly and to evaluate the long-term clinical outcomes.

HYPOTHESIS

Conservative treatment can be an option in the management of static macrodactyly of the foot in children.

MATERIAL AND METHODS

We retrospectively included 24 feet in 19 patients seen consecutively. There were 12 primary and 12 secondary types. The macrodactyly was static in 9 cases and progressive in 15 cases. The treatment consisted in either conservative procedures or amputation of the segment. All patients completed the Oxford Ankle Foot Questionnaire for Children (OxAFQ-C) to evaluate their quality of life, shoe wear issues, and satisfaction with their treatment.

RESULTS

Mean age at first surgery was 5.8 years (range, 0.5-11.5) and the mean interval between two procedures was 2.3 years (range, 0.3-5.5). Mean number of procedures per foot was 2.2 par pied (range, 0-7). All 9 static forms were managed conservatively. Amputation was performed in 11 of the 15 progressive forms. The mean number of procedures was significantly higher in the progressive forms (4.1 vs. 1.5/pied; p=0.006). Two patients died during follow-up. The remaining 17 patients, with 22 affected feet (primary and secondary in 11 cases; progressive in 14 cases and static in 8 cases) were re-evaluated. Mean follow-up was 9.4 years (range, 2.7-20.6). The final OxAFQ-C score was 46/60 (range, 18-58). Of the 17 patients, 86% would be willing to repeat the same surgical procedures and 77% were satisfied with their treatment at last follow-up. We found no differences between the groups managed with amputation and with conservative treatment regarding quality of life, satisfaction, or shoe size difference.

CONCLUSIONS

Conservative treatment deserves a place in the treatment of static macrodactyly of the foot in children. Regarding amputation of the segment in progressive forms, it is important to reassure the patients and parents about the expected results but also to inform them about the risk of requiring repeat surgical procedures.

LEVEL OF EVIDENCE

IV, retrospective study.

A systematic review of the safety and efficacy of currently used treatment modalities in the treatment of patients with PIK3CA-related overgrowth spectrum

BACKGROUND

PIK3CA (activating mutations of the p110α subunit of phosphatidylinositol 3-kinases)-related overgrowth spectrums (PROS) include a variety of clinical presentations that are associated with hypertrophy of different parts of the body. We performed a systematic literature review to assess the current treatment options and their efficacy and safety for PROS.

METHODS

A literature search was performed in Embase, MEDLINE (Ovid), Web of Science Core Collection, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and Google Scholar to retrieve studies on the treatment of hypertrophy in PROS. Randomized controlled trials, cohort studies, and case series with ≥10 patients were included in the present review. The titles, abstracts, and full text were assessed by two reviewers independently. The risk of bias was assessed using the Newcastle-Ottawa scale.

RESULTS

We included 16 studies of the treatment of hypertrophy in PROS patients, 13 (81.3%) from clinical retrospective studies and 3 (13.7%) from prospective cohort studies. The risk of bias grade was low for 2, medium for 12, and high for 2 studies. Of the 16 studies, 13 reported on surgical treatment and 3 reported pharmacologic treatment using phosphatidylinositol-3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathway inhibitors in PROS patients. In 3 studies, PROS was defined by a mutation in the PIK3CA gene, and 13 studies relied on a clinical definition of PROS. Surgical therapy was beneficial for a specific subgroup of PROS (macrodactyly). However, little has been reported concerning surgery and the potential benefits for other PROS entities. The reported side effects after surgical therapy were mostly prolonged wound healing or scarring. PI3K/mTOR pathway inhibition was beneficial in patients with PROS by reducing hypertrophy and systemic symptoms. The adverse effects reported included infection, changes in blood count, liver enzymes, and metabolic measures.

CONCLUSIONS

Surgery is a locally limited treatment option for specific types of PROS. A promising treatment option for PROS is pharmacologic PIK3CA inhibition. However, the level of evidence on the treatment of overgrowth in PROS patients is limited.

[Clinical characteristics of 170 cases of macrodactyly]

OBJECTIVE

To analyze the clinical characteristics of 170 cases of macrodactyly.

METHODS

Medical records of 170 macrodactyly patients at Beijing Jishuitan Hospital between March 2006 and October 2019, including demographic characteristics, clinical presentations, anatomical distributions, X-rays, pathological findings, and treatments, were reviewed. PIK3CA mutation analyses of 12 patients were also reviewed.

RESULTS

Disease incidence was similar across sex and geographical regions. Multiple-digit involvement was 3.9 times more frequent than single-digit involvement. In upper deformit: ies, the index finger, middle finger and thumb were mostly involved, and the second and third toes were the most affected on the foot. Two digits were affected more often than three digits, with the affected multiple digits were adjacent most time. The cases of progressive macrodactyly, in which the affected digits grew at a faster rate than the unaffected digits, were found more than static type. Most of progressive macrodactyly were noticed at birth. In terms of nerve involvement, affected fingers mostly occurred in the median nerve innervation area (79.4%) accompanied by median nerve and brunches enlargement and fat infiltration, i.e., nerve territory oriented; affected toes mostly occurred in the medial plantar nerve innervation area (89.1%), marked with overgrowth of adipose tissue with a lesser degree of neural overgrowth, i.e., lipomatous. Only 17 cases had comorbid of syndactyly. The metacarpal bones were involved only in progressive type of macrodactyly. Ten of the 12 cases subjected to PIK3CA mutation analysis were positive. Among all tested specimens, PIK3CA mutation levels ranged from 7% to 27%. In terms of tissue sources in which a mutation was found, adipose tissue had the highest mutation detection rate, followed by nerve and skin. All the DNA samples of blood from the 12 PIK3CA mutation-positive patients were negative.

CONCLUSION

Macrodactyly fingers mostly occurred in the median nerve innervation area accompanied by median nerve and brunches enlargement and fat infiltration. The index and middle fingers were mostly involved. Macrodactyly toes mostly occurred in the medial plantar nerve innervation area, marked with overgrowth of adipose tissue with a lesser degree of neural overgrowth. The second and third toes were the most affected on the foot. A high proportion (83%) of isolated macrodactyly patients carry activating PIK3CA mutations. Adipose, nerve, and skin tissues provide the highest PIK3CA mutation detection yield among all types of tissue studied.

A patient with macrodystrophia lipomatosa bilaterally affecting the entire upper extremity: reporting of a rare case and literature review

The patient, a 58-year-old Asian female, had the progressive, bilateral overgrowth of the entire upper extremity since her childhood and has undergone debulking surgery twice in her country. However, overgrowth progressed after surgery. The patient was diagnosed with Macrodystrophia lipomatosa (MDL) by physical and imaging findings in our departments.

Phalangectomy combination double-pedicled digital artery flap for second-toe macrodactyly reconstruction: A case report

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Pedal macrodactyly is a rare form of congenital deformity.

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The goal of most macrodactyly is to reconstruct the affected toes to the normal size.

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We report a macrodactyly with an enlargement of the right foot index and middle toes.

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The patient underwent phalangectomy double-pedicle medial and lateral digital artery flap.

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Satisfactory results were noted at evaluation after surgery.

Introduction

Pedal macrodactyly is a rare form of congenital deformity in which the toes and underlying structures are enlarged. The goal of most macrodactyly reconstruction surgeries is to reconstruct the affected toes to resemble the normal size such that the patient is able to wear shoes of the same size.

Case presentation

We report a three-year-old female patient presenting with an enlargement of the right foot index and middle toes. The anomaly was noticed at two months of age and grew progressively. X-ray imaging revealed enlarged bones and soft-tissue hypertrophy proximal to the distal phalanx of the second and third digits. There was no history of other systemic or syndromic diseases. The patient underwent phalangectomy surgery involving reduction of the fibrofatty tissue, double-pedicle medial and lateral digital artery flap. Satisfactory results were noted at evaluation two months of after surgery.

Conclusion

Macrodactyly reduction surgeries are generally composed of several kinds of surgical techniques to provide the best results. The management of macrodactyly depends on the surgeon’s experience while considering the most suitable surgical technique to be performed in each case. Therefore, it was deemed necessary to report this case and its surgical technique. We hope that this case report will enrich the existing literature and be useful for the management of macrodactyly cases.

Clinical characteristics of 93 cases of isolated macrodactyly of the foot in children

BACKGROUND

The purpose of this study was to describe the clinical characteristics of macrodactyly of the foot through a large cohort of cases to further understand this rare entity.

METHODS

Medical records, clinical photographs, plain radiographs, pathological findings, and intraoperative photographs of 95 feet of 93 patients were reviewed. Data including age; sex; laterality; ethnicity; birthplace; family history; and history of gestation, environment, whether smoking, or drinking during pregnancy were collected and analyzed.

RESULTS

Female patients (60%), left foot (56%), and static overgrowth (63%) were more prominent in the study cohort. Southern provinces (74%) and Han Chinese ethnicity (95%) predominated in terms of geographical region and demographic distribution, respectively. Multiple-toe involvement was 2.01-times more frequent than single-toe involvement. All five toes were involved with midline toes being most frequently affected overall and a medial distribution being more common than a lateral one. The forefoot was affected in 90 feet. The affected areas (toes and forefeet) were mostly located in the innervation of the affected medial plantar nerve (91%). The nerves showed enlargement in 49 feet, fatty infiltration in 25, a tortuous course in one, and were normal in 10 feet. Only six feet involved the musculature. Enlargement of phalanges and metatarsals were observed in 92 and 57 feet, respectively, and advanced bone maturation was seen in 63 feet. Twenty-two cases had syndactyly.

CONCLUSIONS

Macrodactyly of the foot is a rare congenital malformation with diverse clinical manifestations and multiple elements' involvement. It also presents the characteristics of nerve-mediated overgrowth and "nerve territory-oriented" deformity similar to that of macrodactyly of the hand.

Isolated Acquired Macrodactyly of the Left Fourth Toe

Macrodactyly is a rare congenital disorder affecting the digits of hands and feet. It is often distressing for both parents and children. Surgical options range from soft tissue debulking with or without osteotomy and physeal arrest to simple or ray amputation. Although amputation is generally reserved for the severe progressive variant of macrodactyly and revision surgery, there is controversy regarding whether initial amputation or debulking is the best approach. We present a case of isolated macrodactyly of a minor toe, where debulking showed superior results.

Macrodactyly of the foot resulting from plantar nerve impairment

The role of the plantar nerve in the pathogenesis of macrodactyly of the foot is unknown. We investigated the distribution of affected toes and forefoot in 27 feet of 26 patients with pedal macrodactyly, and how this relates to innervation of the affected plantar nerve. A preoperative ultrasound examination was performed to determine the diameter and structure of the plantar nerve. Histologic findings were recorded during surgery. The microstructure of affected plantar nerves was evaluated by hematoxylin-eosin staining, while S100 expression was assessed by immunofluorescence analysis. Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) gene mutation in the affected nerve tissue was detected by Sanger DNA sequencing. The affected toes and forefoot involved innervation of the medial plantar nerve in 25/27 feet, the lateral plantar nerve in one foot, and both medial and lateral plantar nerves in one foot. All affected plantar nerves, which were accompanied by a fatty strip, were surrounded by or infiltrated with fat. The affected plantar nerves showed enlargement, a tortuous course, fatty infiltration, or a combination of these. Pathologic changes in affected plantar nerves involved only the epineurium and not the perineurium or endoneurium. Expression of the Schwann cell marker S100 was absent in some areas of affected nerves. Sequencing of PIK3CA exons identified a gain-of-function mutation (p.His1047Arg) in affected plantar nerves. These results indicate that pathologic impairment of the plantar nerve can lead to macrodactyly of the foot, which may be considered as a nerve trunk disease.

Clinical Characteristics of 90 Macrodactyly Cases

PURPOSE

Macrodactyly is a rare, nonhereditary congenital deformity. Digital enlargement in macrodactyly involves all tissue types and presents alone or as part of a congenital deformity syndromes. Macrodactyly treatment largely depends on surgeons' experience and knowledge. Because there is a paucity of large cohort studies of macrodactyly in the literature, our goal was to retrospectively analyze macrodactyly cases in order to define a better system for diagnosis, classification, and prognosis.

METHODS

Medical records of 90 Chinese macrodactyly patients, including demographic characteristics, clinical presentations, anatomical distributions, x-rays, pathological findings, and treatments, were reviewed. Genetic analyses of 12 patients were also reviewed.

RESULTS

Disease incidence was similar across sex and geographical regions. Multiple-digit involvement was 2.6 times more frequent than single-digit involvement. The index finger, middle finger, and thumb were most commonly involved. Two digits were affected more often than 3, with the affected digits adjacent in most cases. The affected digit was in the median nerve innervation distribution in 79% of cases and was accompanied by enlargement and fat infiltration of the median nerve. Seven cases had syndactyly. Ten of the 12 cases subjected to PIK3CA mutation analysis were positive.

CONCLUSIONS

Macrodactyly represents a heterogeneous group of conditions, without significant sex or geographical predilection, which is usually present at birth. A high PIK3CA mutation-positive rate in affected tissues suggests a similar cellular mechanism for overgrowth in patients with various clinical presentations.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic IV.

Activating PIK3CA mutation promotes osteogenesis of bone marrow mesenchymal stem cells in macrodactyly

Macrodactyly is a disabling congenital disease characterized by overgrowth of soft tissues and bones, which leads to finger enlargement and joint deformity. The mechanism of bone overgrowth in macrodactyly was rarely understood. In our study bone manifestations of three macrodactyly patients were analyzed by micro-CT. PIK3CA mutation was detected by next-generation sequencing (NGS) of a tumor gene-panel. The PI3K/AKT/mTOR pathway activation and target genes were analyzed. The osteogenic potential of macrodactyly-derived bone marrow mesenchymal stem cells (MAC-BMSCs) was compared with polydactyly-derived bone marrow mesenchymal stem cells (PD-BMSCs). PIK3CA inhibitors were tested for proliferation and osteogenesis potential of MAC-BMSCs. Activating PIK3CA mutations and activation of PI3K/AKT/mTOR pathway were detected in all MAC-BMSCs. MAC-BMSCs had enhanced osteogenesis potential compared with PD-BMSCs. PIK3CA knockdown by shRNA or BYL719 treatment significantly reduced osteogenic differentiation capacity of MAC-BMSCs. RNA-Seq and qRT-PCR revealed the upregulation of distal-less homeobox 5 (DLX5) in MAC-BMSCs compared with PD-BMSCs. The osteogenic potential of MAC-BMSCs was inhibited by DLX5 knockdown, indicating that DLX5 is a downstream target of PIK3CA activation-mediated osteogenesis. This study revealed that osteogenic differentiation in MAC-BMSCs is enhanced by PIK3CA activation mutation through PI3K/AKT/mTOR signaling pathway and can be reversed by PIK3CA knockdown or drug inhibition.

Strengthening the association of lipomatosis of nerve and nerve-territory overgrowth: a systematic review

OBJECTIVE

Lipomatosis of nerve (LN) is a massive enlargement of a nerve due to abundant proliferation of adipose and fibrotic tissue within the epineurium—part of the spectrum of adipose lesions of nerves, including intra- and extraneural lipomas. LN has been frequently associated with soft-tissue and/or osseous overgrowth. Unfortunately, much confusion exists since many names have been used for LN (e.g., fibrolipomatous hamartoma, macrodystrophia lipomatosa, and so on). To better understand this condition and to evaluate its association with nerve-territory overgrowth, the authors attempted to compile the world’s literature on published LN cases.

METHODS

PubMed and Google Scholar databases were searched to identify published articles on LN cases, using a variety of terms. Publications in all languages were assessed. All publications with cases determined likely to be LN were read. Cases that provided clear clinicopathological and/or radiological evidence of LN were labeled as “definite” and cases that demonstrated features of LN (e.g., nerve-territory overgrowth) but lacked definite proof of nerve involvement were labeled as “probable.”

RESULTS

Initial screening revealed a total of 2465 papers. After exclusions, 281 publications reported cases with a definite diagnosis of LN and 120 articles reported cases with a probable diagnosis of LN. The authors identified 618 definite and 407 probable cases of LN. Sex distribution was balanced (51% female). Early diagnosis was common, with two-thirds of patients having symptoms in the 1st decade of life. The most commonly affected nerve was the median nerve (n = 391). Nerve-territory overgrowth was common (62% definite LN; 78% combined cases); overgrowth was exclusive to the territory of the affected nerve in all cases but 5.

CONCLUSIONS

The authors present a comprehensive review and analysis of the literature of LN cases. One of the main findings was the nerve-territory overgrowth was associated with LN, especially when present earlier in life. The authors believe that all cases of LN associated with overgrowth can be explained on anatomical grounds, even in the few reported cases in which this is not immediately obvious.

A Novel Method of Treatment of Macrodactyly with Digital Nerve Resection and Nerve Allograft

Supplemental Digital Content is available in the text.

Macrodactyly is a rare and debilitating pediatric hand anomaly that has historically been treated with amputation. Recent advances in our understanding of macrodactyly have increasingly implicated the digital nerve as the underlying cause of the condition. In addition, much progress has been made toward digital salvage in treating macrodactyly. Modern techniques often advocate for digital nerve resection to prevent recurrence and treat the underlying etiology. However, little if any emphasis has been given to sensory reconstruction for purposes of protective sensation and acceptable 2-point discrimination at the volar digital pulp. We report 2 cases of macrodactyly treated with digital nerve resection and nerve allograft reconstruction of large sensory nerve gaps which show early promising sensory outcomes. There remain little if any data on the use of nerve allograft in pediatric populations, and its application in the treatment of macrodactyly. This technique permits digit salvage with the potential for improved sensory outcomes without the donor morbidity of autologous nerve harvest.

Macrodystrophia Lipomatosa: A Single Large Radiological Study of a Rare Entity

Introduction:

We present one of the largest case series of Macrodystrophia lipomatosa, a rare congenital disorder of localized gigantism characterized by overgrowth of all the mesenchymal elements, predominantly involving the fibroadipose tissue.

Aims:

To detail the radiological features, pattern of distribution, associated conditions and to suggest an appropriate terminology to describe the condition.

Methods and Material:

It is a retrospective study. Data from PACS server dating from 2000 and 2018 was used. The cases with isolated enlarged limb or digit/digits with or without nerve involvement were included in the study.

Statistical Analysis Used:

Frequency and percentage were used for analysis of categorical variables.

Results:

A total of 31 cases was included for the final analysis, out of which 19 were males and 12 were females. Unilateral limb involvement was seen in 30 cases. The most common pattern identified was the ’nerve territory oriented’ type in 28 cases confined to the hand or foot, ’diffuse or pure lipomatous’ type in one case and mixed type was seen in two cases. The most common nerve territory involved was along the median nerve in the upper limb and along the medial plantar nerve in the lower limb. Neural involvement was seen in 16 cases of the upper limb and 10 cases of the lower limb. Syndactyly was seen in two cases, polydactyly in one case and symphalangism in one case.

Conclusions:

A diagnosis of macrodystrophia lipomatosa can be confidently made in cases with congenital isolated limb or digit/digits enlargement with or without fibrolipohamartoma of nerve. Radiographs and ultrasound are sufficient along with clinical examination to make accurate diagnosis. MRI is useful for assessing the extent and for planning surgery.

Macrodactyly: decision-making and surgery timing

Macrodactyly is a rare condition in which fingers, hands or limb growth is unregulated, resulting in overgrowth of tissues in the affected extremities. It is critical to properly assess these extremities for signalling pathway, psychological impact and potential surgical intervention, to achieve the best possible outcome for each patient. Treatment approaches can vary, and patient and family expectations weigh heavily on care complexity. Common surgical procedures may include epiphysiodeses, osteotomies, debulking procedures, carpal tunnel releases, toe transfers and amputations. The selection and timing of these surgeries is a vital component of the approach, as delayed healing and excessive scarring may occur. The purpose of this review is to assist in the navigation of decision-making and surgical timing for patients presenting with overgrowth manifesting itself as macrodactyly.

An investigation of PIK3CA mutations in isolated macrodactyly

Somatic PIK3CA mutations may relate to pathogenesis of isolated macrodactyly. We set up to test the association between PIK3CA mutations with isolated macrodactyly in order to establish a more accurate and molecular mechanism-based diagnosis and classification. DNA extracted from affected tissues in 12 individuals with isolated macrodactyly was tested for PIK3CA mutation using targeted Sanger DNA sequencing. Ten patients had macrodactyly in the foot and two in the hand. Nine of the 12 patients were found to carry a low-level, mosaic PIK3CA mutation. The mutations identified, p.His1047Arg, p.His1047Leu, p.Glu545Lys, and p.Glu542Lys, are codons frequently mutated in cancers. Among all tissues tested, adipose had the highest mutation detection rate, followed by nerve and skin. Our results indicate that a high proportion of isolated macrodactyly patients carry a pathogenic PIK3CA mutation. Affected adipose, nerve and skin tissues are ideal for PIK3CA mutation analysis.

Morphological and neurophysiological impairment of the nerve in type II macrodactyly

Background

Macrodactyly is a congenital malformation characterized by aggressive overgrowth of multiple tissues, including subcutaneous fat, nerves, and bones in digits or limbs. In type II macrodactyly, the peripheral nerve is enlarged; however, the morphological and functional characteristics of the affected peripheral nerves have rarely been evaluated.

Methods

In this research, six macrodactyly patients and three polydactyly patients (control) were studied. Pre-operative sensory nerve action potential and intra-operative nerve action potential tests were performed. The microstructure and ultrastructure of the enlarged nerves were observed and neurofilament (NF) expression was evaluated using immunofluorescent staining.

Results

Axon impairment of the digital nerves originating from the median nerve (MN) was observed. A compensatory reinnervation from the ulnar nerve (UN) was found in two of the six patients, and significant morphological changes were observed in the enlarged nerve. The myelinated nerve fibers decreased, the lamellar structure of the myelin sheath changed, and the density of the NFs of the unmyelinated fibers decreased. There was aberrant distribution of NFs in the macrodactylous nerve tissues. In patients with compensatory UN reinnervation, the number of myelinated and unmyelinated fibers increased to normal levels; however, the diameter of the myelinated fibers apparently decreased.

Conclusions

The morphology and function of the macrodactylous enlarged nerve was impaired in type II macrodactyly patients; however, the unaffected UN partially compensated for the lost function of the affected MN under specific situations. Electrophysiological tests should be performed to determine the function of the affected nerve and surgical treatment for type II macrodactyly could be refined.

Ray resection in paediatric population

AIM

Evaluation of clinical and functional outcome of ray resection in paediatric population and description of key aspects of surgical technique.

MATERIAL AND METHODS

We performed a retrospective review of all patients undergoing surgery between 2010-2015.

INCLUSION CRITERIA

one or more ray resections of the hand and a minimum of one year follow-up. Evaluation of clinical characteristics, functional and cosmetic results, complications, need for psychological support and patient or family satisfaction.

RESULTS

Four patients met the inclusion criteria. The mean age at surgery was 5 years (range, 1-14 years). Aetiology was: fibrolipomatous hamartoma, traumatic amputation, radial deficiency and complex syndactyly. Second ray was resected in three patients and third and fourth ray in one. No finger transfer was performed. No immediate post-operative complications were found at the final evaluation. None of them needed psychological support. All the patients showed excellent clinical and functional results with a high grade of satisfaction.

DISCUSSION

Ray resection of the hand has been used as salvage procedure in patients with vascular lesions, tumours, trauma, infections or congenital malformations. There are only a few published studies including small samples in adults or case reports, with no references in the paediatric population.

CONCLUSION

Ray resection of the hand is a useful and safe technique in paediatric population, obtaining excellent cosmetic and functional results in those cases in which it is impossible to preserve one or more fingers.

Ray amputation for the treatment of foot macrodactyly in children

Macrodactyly of the foot is a rare but disabling condition. We present the results of surgery on 18 feet of 16 patients, who underwent ray amputation and were followed-up for more than two years at a mean of 80 months (25 to 198).

We radiologically measured the intermetatarsal width and forefoot area pre-operatively and at six weeks and two years after surgery. We also evaluated the clinical results using the Oxford Ankle Foot Questionnaire for children (OxAFQ-C) and the Questionnaire for Foot Macrodactyly.

The intermetatarsal width and forefoot area ratios were significantly decreased after surgery. The mean OxAFQ-C score was 42 (16 to 57) pre-operatively, improving to 47 (5 to 60) at two years post-operatively (p = 0.021). The mean questionnaire for Foot Macrodactyly score two years after surgery was 8 (6 to 10).

Ray amputation gave a measurable reduction in foot size with excellent functional results. For patients with metatarsal involvement, a motionless toe, or involvement of multiple digits, ray amputation is a clinically effective option which is acceptable to patients.

Cite this article: Bone Joint J 2015;97-B:1364–9.

Surgical Treatment of Macrodactyly

Macrodactyly, enlargement of one or multiple digits, was described in the literature nearly 200 years ago. This is an exceptionally uncommon diagnosis that has led to a paucity of descriptive literature on the treatment options. Because the literature is scarce, and the frequency with which hand surgeons encounter macrodactyly is even scarcer, treatment can be a formidable task often left exclusively to those trained in congenital hand deformity. This article presents our algorithm and surgical techniques for dealing with children with macrodactyly in such a way that should make a complex problem more easily approachable.