Dysplasia epiphysealis hemimelica: A histological comparative study with osteochondromas

Abstract

PurposeDysplasia epiphysealis hemimelica (DEH) is a rare developmental disorder resulting in epiphyseal overgrowth. Based on histological appearance, it is often described as an osteochondroma or osteochondroma-like lesion, although clinical differences exist between DEH and osteochondromas. The aim of this study was to test whether DEH and osteochondromas are histologically identical diseases.MethodsTissue samples of two age- and gender-matched cases with DEH and hereditary multiple exostoses were histologically compared. Sections were stained with Safranin-O for detection of proteoglycans and immunohistochemistry was performed for detection of collagen type II, collagen type X as a marker of hypertrophic chondrocytes and Sox9 as a marker of proliferative chondrocytes. Due to the rarity, descriptions of the included DEH patients were outlined.ResultsHistologically, chondrocyte clusters in a fibrillary matrix, a thick disorganised cartilage cap and ossification centres with small amounts of unabsorbed cartilage, were observed in DEH. In contrast, cartilage organisation of osteochondromas displays characteristics of the normal growth plate. Collagen type II was clearly detected in the cartilaginous extracellular matrix in osteochondromas, while weak expression was observed in DEH. Collagen type X was not detected in DEH, while expressed in the matrix surrounding hypertrophic chondrocytes in osteochondromas. Sox9 staining was positive in hypertrophic chondrocytes in osteochondromas, while expressed in nuclei of chondrocyte clusters in DEH.ConclusionBoth morphological and immunohistological differences were observed in histological sections of DEH and osteochondromas. These results support the previously identified clinical, radiological and genetic differences and imply a different aetiology between DEH and osteochondroma formation.

Asymptomatic Dysplasia Epiphysealis Hemimelica of the Shoulder in a Skeletally Mature Patient with Normal Function

“…Although it has been described as a rare developmental disorder, recent research has greatly advanced our understanding of the pathobiology and articular involvement of DEH. Erroneously described as an osteochondroma or osteochondroma-like lesion despite its epiphyseal location, some studies demonstrated that DEH lesions differ pathologically from osteochondromas [9, 15]. In a comparative histological study, Stevens et al found that in DEH lesions chondrocyte clusters are seen in conjunction with a thick disorganized cartilage cap and ossification centers with small amounts of unabsorbed cartilage, whereas in osteochondroma lesions cartilage is more organized and displays characteristics of the normal growth plate [15].…”

“…Erroneously described as an osteochondroma or osteochondroma-like lesion despite its epiphyseal location, some studies demonstrated that DEH lesions differ pathologically from osteochondromas [9, 15]. In a comparative histological study, Stevens et al found that in DEH lesions chondrocyte clusters are seen in conjunction with a thick disorganized cartilage cap and ossification centers with small amounts of unabsorbed cartilage, whereas in osteochondroma lesions cartilage is more organized and displays characteristics of the normal growth plate [15]. In addition, differently from osteochondroma lesions, collagen type II is weakly expressed and collagen type X is not detected in DEH lesions [15].…”

“…In a comparative histological study, Stevens et al found that in DEH lesions chondrocyte clusters are seen in conjunction with a thick disorganized cartilage cap and ossification centers with small amounts of unabsorbed cartilage, whereas in osteochondroma lesions cartilage is more organized and displays characteristics of the normal growth plate [15]. In addition, differently from osteochondroma lesions, collagen type II is weakly expressed and collagen type X is not detected in DEH lesions [15]. In another study, Bovée et al observed that some gene pathways, such as EXT1 and EXT2, implicated in osteochondroma lesions, are not detected in DEH lesions [16].…”

“…Regardless of DHE stratification into intra- or extra-articular lesion, total resection of the mass is one of the most common described interventions in immature skeletons [1, 7]. Massive ossification of the cartilaginous mass and early OA have been reported to increase over long follow-up evaluation, although few studies addressed those consequences in the adult patient [1, 7, 15]. Braman and Steward presented a case of a 16-year-old male who underwent a left shoulder custom hemiarthroplasty due to humeral head collapse after failed epiphysiodesis for continued growth of DEH at the age of 14 [12].…”

Dysplasia epiphysealis hemimelica combined with contralateral accessory scaphoid bone

“…It also has been reported that EXT1 and EXT2 were found in osteochondroma by genetic examination, that may provide an appropriate evidence when two pathological examinations are similar. [12]…”