The calcaneus: normal and abnormal

A radiological diagnostic approach to tumours and tumour-like lesions of the calcaneus

OBJECTIVE

The calcaneus is a rare location for the development of primary bone tumours. The purpose of the study is to review the imaging findings in a cohort of patients presenting with tumours and tumour-like lesions of the calcaneus and to develop a more structured approach to the diagnosis of calcaneal lesions.

METHODS

A retrospective study with a collection of 167 cases of calcaneal tumours and tumour-like lesions from our tertiary orthopaedic oncology institution over a period of 13 years. Cases were reviewed by two consultant musculoskeletal radiologists and the location of the lesion within the calcaneus and demographics of the patient were noted for each case. A diagnostic algorithm, which is based on patient age and tumour location, was then extrapolated.

RESULTS

Out of the 167 cases, we identified 24 different calcaneal pathologies which included both tumours and tumour-like lesions. The most common being simple bone cysts (18.3% of cases) and intra-osseous lipoma (15% of cases) sited in the diaphyseal equivalent of the calcaneus. A diagnostic algorithm was formulated, which describes the most common location of the different pathologies including both benign and malignant pathologies, subdivided by age.

CONCLUSION

Our algorithm should help the radiologist narrow down the differential diagnosis when evaluating calcaneal lesions.

ADVANCES IN KNOWLEDGE

This article provides a radiological approach to calcaneal lesions.

Radionuclide Imaging of Infection and Inflammation in Children: a Review

With the exception of radiolabeled monoclonal antibodies, antibody fragments and radiolabeled peptides which have seen little application in the pediatric population, the nuclear medicine imaging procedures used in the evaluation of infection and inflammation are the same for both adults and children. These procedures include (1) either a two- or a three-phase bone scan using technetium-99m methylene diphosphonate; (2) Gallium 67-citrate; (3) in vitro radiolabeled white blood cell imaging (using ¹¹¹Indium-oxine or ^99mTechnetium hexamethyl-propylene-amine-oxime-labeled white blood cells); and (4) hybrid imaging with ¹⁸F-FDG. But children are not just small adults. Not only are the disease processes encountered in children different from those in adults, but there are developmental variants that can mimic, but should not be confused with, pathology. This article discusses some of the differences between adults and children with osteomyelitis, illustrates several of the common developmental variants that can mimic disease, and, finally, focuses on the increasing use of ¹⁸F-FDG PET/CT in the diagnosis and response monitoring of children with infectious and inflammatory processes. The value of and need for pediatric specific imaging protocols are reviewed.

A rare probable chondroblastoma of the calcaneus in a pre-Columbian subadult from Illinois

Discrete cystic or tumorous intraosseous lesions can arise from a variety of benign and malignant conditions as well as trauma and infection. They are clinically rarely observed in the calcaneus. A fourteen-to-seventeen-year-old subadult recovered from a Late Woodland (∼AD 800-1100) period mortuary context in the Mississippi River Valley of central Illinois presents with a single lytic intraosseous lesion on the posterior right calcaneus that bilaterally perforates the cortex. The lesion, although primarily anterior to the epiphyseal plate, does breach it. There is also a small perforation of the outer cortex of the epiphysis above the insertion of the Achilles' tendon. The lesion is well-defined with a primarily spongy cancellous interior margin. On the body of the calcaneus, there is periostosis and a slightly expansive endosteal reaction. Comparative radiographic assessments undertaken to differentially diagnose the lesion indicate that it was likely not malignant. Based on the posterior location, the radiographic signature, the bilateral cortical perforation and the breach of the epiphysis, the lesion is best interpreted as a chondroblastoma.

Benign and malignant tumors of the foot and ankle

Pain and focal masses in the foot and ankle are frequently encountered and often initiate a workup including imaging. It is important to differentiate benign lesions from aggressive benign or malignant lesions. In this review, multiple examples of osseous and soft tissue tumors of the foot and ankle will be presented. Additionally, the compartmental anatomy of the foot and ankle will be discussed in terms of its relevance for percutaneous biopsy planning and eventual surgery. Finally, a general overview of the surgical management of benign, benign aggressive and malignant tumors of the foot and ankle will be discussed.

Can we make a diagnosis with radiographic examination alone in calcaneal apophysitis (Sever's disease)?

The purpose of this study was to investigate whether the identification of Sever's disease is reliable with radiographs alone. Eighty foot radiographs (50 boys with calcaneal apophysitis and 30 healthy boys) were included in this study. Two consultant orthopaedic surgeons were instructed to make a diagnosis without clinical information on the patients. Radiologic assessments were performed in random order by each observer on two separate occasions, at least 3 weeks later. kappa-statistics were used to establish a relative level of agreement between observers for the two readings and between separate readings by the same observer. Observer A made 22 true (27.5%) diagnoses, whereas observer B made 56 true (70%) diagnoses at the first assessment. Interobserver agreement was rated as slight (kappa-value, 0.190). Observer A made 40 true (50%) diagnoses, whereas observer B made 52 true (65%) diagnoses at the second assessment. Interobserver agreement was rated as slight (kappa-value, 0.039). Intraobserver reproducibility was rated as fair for both observers (kappa-value, 0.369 for observer A and 0.253 for observer B). The results of this study showed that the radiologic identification of calcaneal apophysitis without the absence of clinical information was not reliable. Radiologic findings that were attributed to Sever's disease showed a wide variation between independent observers and between separate readings by the same observer. The diagnosis of calcaneal apophysitis is a clinical decision and radiographic assessment seems to be unnecessary.

Juvenile intraosseous gout of the calcaneus

Gout presenting as an osteolytic lesion is exceedingly rare in children with asymptomatic hyperuricemia. We report the clinical and radiological presentation of intraosseous gout in a 13-year-old boy.

Should calcaneal fractures be treated surgically? A meta-analysis

A MEDLINE search from 1980 through 1996 revealed 1845 articles dealing with calcaneal fractures. Six of these articles that compared operative versus nonoperative treatment for displaced calcaneal fractures met the minimum criteria for inclusion in a meta-analysis. A statistical summary of information across the six articles revealed a trend for surgically treated patients to be more likely to return to the same type of work as compared with nonoperatively treated individuals. There also was a trend for nonoperatively treated patients to have a higher risk of experiencing severe foot pain than did operatively treated patients. Unfortunately, none of the other outcomes could be summarized formally across studies using statistical techniques because of variability in reporting across studies. Although the tendency was always for operatively treated patients to have better outcomes (reaching statistical significance in some of the articles), the strength of evidence to recommend operative treatment for displaced intraarticular calcaneal fractures remains weak. A large prospective randomized controlled trial should be able to answer this question.

The calcaneus: applications of magnetic resonance imaging

The calcaneus is the largest bone in the foot and is an important primary weightbearing structure. Pathologic processes that affect this bone may manifest in a variety of clinical presentations, including pain, abnormal motion, instability, or fracture. The purpose of this article is to present a pictorial essay of the wide spectrum of pathologic entities that may affect the calcaneus, emphasizing applications of magnetic resonance imaging and characteristic magnetic resonance features of these processes.

Unusual small bone metastases from epithelial malignancies: diagnosis by fine-needle aspiration cytology with histologic confirmation

Although epithelial malignancies can have bone metastases, involvement of small bones is exceedingly rare, representing either first manifestation of an occult carcinoma or late disseminated disease. Small bone metastases may mimic primary skeletal diseases leading to misdiagnosis and delayed treatment. We report three cases of metastatic epithelial malignancies diagnosed by computed tomography (CT)-guided fine-needle aspiration (FNA) biopsy in two patients with lytic calcaneal lesions and a patellar lesion in a third patient; all with histologic confirmation. Case 1, a 63-year-old female, presented with heel pain. FNA and tissue biopsy of the calcaneus revealed a clear cell malignancy consistent with a renal primary. Follow-up abdominal CT scan revealed a renal lesion consistent with renal cell carcinoma. Case 2, a 37-yr-old male with squamous cell carcinoma of the esophagus, presented with foot pain. FNA and tissue biopsy of the calcaneous revealed metastatic squamous cell carcinoma. Case 3, a 52-yr-old male with a history of squamous cell carcinoma of floor of mouth, presented with knee pain and swelling. FNA and tissue biopsy of the patella revealed metastastic squamous cell carcinoma. To the best of our knowledge, this is the first complete FNA cytology report with histologic confirmation of unusual small bone metastases of the feet and patella from epithelial malignancies and shows the value of FNA cytology in establishing a correct diagnosis, and excluding primary skeletal diseases.