Chronic abdominal pain caused by heterotopic ossification with functioning bone marrow: a case report and review of the literature

Heterotopic ossification of the anterior abdominal wall

Heterotopic ossification (HO) is a bone formation in a tissue other than the skeletal system. It is more often seen as a complication of orthopedic surgery; however, it is a pathological condition that might be observed during the healing process of abdominal incisions in the midline. The aim of this study is to present a case of a 63-year-old male patient with the complaints of induration and pain on the region of his previous incision through which he had been operated for achalasia. HO is also discussed in the light of the current literature.

Heterotopic Mesenteric Ossification With Trilineage Hematopoiesis

Heterotopic ossification (HO) histologically refers to extraskeletal bone formation in non-ossifying tissues, most commonly noted in the extremities, buttocks, abdominal wall, and hip joints. HO developing in the mesentery (heterotopic mesenteric ossification, HMO) is very rare, with fewer than 100 cases reported in the literature. It usually occurs in adult male patients with a history of repeated abdominal trauma. So far, only two cases of HMO have been reported with the development of hematopoietic bone marrow. Here, we report the third case of HMO with true trilineage hematopoiesis in a 66-year-old female with suspicious mesenteric-retained foreign material from prior surgical procedures, including hysterectomy for endometrial adenocarcinoma and multiple repairs for incisional hernia.

Neurogenic Heterotopic Ossifications Recapitulate Hematopoietic Stem Cell Niche Development Within an Adult Osteogenic Muscle Environment

Hematopoiesis and bone interact in various developmental and pathological processes. Neurogenic heterotopic ossifications (NHO) are the formation of ectopic hematopoietic bones in peri-articular muscles that develop following severe lesions of the central nervous system such as traumatic cerebral or spinal injuries or strokes. This review will focus on the hematopoietic facet of NHO. The characterization of NHO demonstrates the presence of hematopoietic marrow in which quiescent hematopoietic stem cells (HSC) are maintained by a functional stromal microenvironment, thus documenting that NHOs are neo-formed ectopic HSC niches. Similarly to adult bone marrow, the NHO permissive environment supports HSC maintenance, proliferation and differentiation through bidirectional signaling with mesenchymal stromal cells and endothelial cells, involving cell adhesion molecules, membrane-bound growth factors, hormones, and secreted matrix proteins. The participation of the nervous system, macrophages and inflammatory cytokines including oncostatin M and transforming growth factor (TGF)-β in this process, reveals how neural circuitry fine-tunes the inflammatory response to generate hematopoietic bones in injured muscles. The localization of NHOs in the peri-articular muscle environment also suggests a role of muscle mesenchymal cells and bone metabolism in development of hematopoiesis in adults. Little is known about the establishment of bone marrow niches and the regulation of HSC cycling during fetal development. Similarities between NHO and development of fetal bones make NHOs an interesting model to study the establishment of bone marrow hematopoiesis during development. Conversely, identification of stage-specific factors that specify HSC developmental state during fetal bone development will give more mechanistic insights into NHO.

Macrophage-derived oncostatin M contributes to human and mouse neurogenic heterotopic ossifications

Neurogenic heterotopic ossification (NHO) is the formation of ectopic bone generally in muscles surrounding joints following spinal cord or brain injury. We investigated the mechanisms of NHO formation in 64 patients and a mouse model of spinal cord injury-induced NHO. We show that marrow from human NHOs contains hematopoietic stem cell (HSC) niches, in which mesenchymal stromal cells (MSCs) and endothelial cells provide an environment supporting HSC maintenance, proliferation, and differentiation. The transcriptomic signature of MSCs from NHOs shows a neuronal imprinting associated with a molecular network required for HSC support. We demonstrate that oncostatin M (OSM) produced by activated macrophages promotes osteoblastic differentiation and mineralization of human muscle-derived stromal cells surrounding NHOs. The key role of OSM was confirmed using an experimental model of NHO in mice defective for the OSM receptor (OSMR). Our results provide strong evidence that macrophages contribute to NHO formation through the osteogenic action of OSM on muscle cells within an inflammatory context and suggest that OSM/OSMR could be a suitable therapeutic target. Altogether, the evidence of HSCs in ectopic bones growing at the expense of soft tissue in spinal cord/brain-injured patients indicates that inflammation and muscle contribute to HSC regulation by the brain-bone-blood triad.

From brain to bone: evidence for the release of osteogenic humoral factors after traumatic brain injury

PRIMARY OBJECTIVE

The aetiology of the increased osteogenesis associated with severe traumatic brain injury (TBI) remains incompletely understood. The purpose of this article is to review the available evidence regarding the release of osteogenic humoral factors after TBI.

RESEARCH DESIGN

This study is presented in the form of a literature review.

METHODS AND PROCEDURES

To obtain suitable references, Pubmed was searched using keywords 'heterotopic ossification', 'brain', 'trauma', 'injury', 'aetiology'.

MAIN OUTCOMES AND RESULTS

Evidence from both clinical and laboratory investigations points to centrally released osteogenic factor(s) that enter the systemic circulation following TBI.

CONCLUSIONS

Further investigation into the identification of these putative osteogenic factor(s), using human tissues and new techniques, is indicated to better understand this phenomenon.

True trilineage haematopoiesis in excised heterotopic ossification from a laparotomy scar: report of a case and literature review

We report a case of true trilineage haematopoiesis in an excised area of heterotopic ossification from an upper mid-line laparotomy scar. Heterotopic ossification is a rare complication of abdominal surgery and usually occurs when upper mid-line incisions are utilised. Whereas cases of heterotopic ossification in abdominal incisions are not exceedingly rare, true trilineage haematopoiesis in such an area of heterotopic ossification, to our knowledge, has only been previously reported once in the English literature.

A Soft-Tissue Calcification: Differential Diagnosis and Pathogenesis

An autopsy of a 72-year-old white male revealed a 30.5 x 5.1 cm vertically aligned heterotopic ossification just deep to a 30.5 cm midline abdominal scar. The ossified mass was determined to be a heterotopic ossification or myostitis ossificans (MO) traumatica resulting from an abdominal surgical incision during life. While, MO traumatica is relatively common accounting for roughly 60-75% of patients with soft-tissue ossification, heterotopic ossification of abdominal incisions are relatively rare and thus infrequently reported. This article details the manifestation of this relatively large heterotopic bone and provides a comprehensive review of the literature and pathogenesis of this unusual ossification. A review of the English literature from 1920 to the present produced only a handful of articles for a total of 185 reported cases. All had bone formed within vertical incisions, usually within 1 year of surgery, and 89% were males. Knowledge of this phenomenon and the variable size at presentation is useful to both the autopsy pathologist and the anthropologist in generating a diagnosis for abnormal calcifications.