Malignant tumors of the sternum in pediatric patients: report of two cases and literature review

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Chronic destructive lesions of the skeleton are relatively rarely observed in the clinical setting by pediatric surgeons and orthopedists. This is probably the reason why every such case becomes critical; such cases involve long-term observation, late diagnosis, and often unjustified and repeated surgical interventions. As a rule, the differential series of such destruction is limited to infectious (more often, tuberculosis) and tumoral processes, and although the former occur more frequently, oncological alertness allows early tumor diagnoses, primarily with the use of radiation and morphological methods.

Sternal lesions occupy a prominent position among chronic destructors, the diagnosis of which in tuberculosis lesions remains unclear [1]. Further, cases of malignant manifestation of the primary sternal lesion in children are extremely rare; thus, we have described two such cases here.

Aim: We aimed to present the clinical and radiation signs of manifestation of malignant sternal lesions in children that enable us to reduce the risk of missing out on such a pathology and the principled stance of early morphological verification.

All patients signed voluntary informed consent forms to participate in the study and/or for the use of their personal data.

Clinical case 1

Patient P., who was 17 years old, was admitted to the clinic with complaints of painless induration in the sternum. According to the patient, the induration was determined during the previous 2 months without visible dynamics. An examination revealed an unchanged general state of the sternum; in the projection of rib 4, on the left, there was an indurated space-occupying lesion without inflammatory changes of the skin. The only remarkable laboratory finding was the increase in the C-reactive protein level to 53 mg/L; the remaining parameters were noted to be within the normal ranges.

The patient was referred to Saint-Petersburg State Research Institute of Phthisiopulmonology on suspicion of tuberculous osteitis of the body of the sternum, based on the results of chest computed tomography that revealed a destructive cavity 21 × 11 × 10 mm in size in the distal part of the body of the sternum with a clear, partially sclerous contour in the lower part and intact surrounding soft tissues (Fig. 1).

 

Fig. 1. Patient P., 17 years old. Computed tomography sections of the chest (bone regimen): a – frontal, b – axial, and c – sagittal. The arrows indicate the cavity of destruction in the body of the sternum

 

Taking into consideration the clinical and radiological data for verifying the diagnosis, it was decided that an open resection biopsy of the sternum should be performed. During the surgery (June 30, 2015), a bone cavity with sclerous margins with dimensions of 30 × 15 mm was observed; it spanned across the entire bone thickness, was located to the left of the central line in the lower part of the sternum, and was filled with brown granulating and necrotic tissue. The pathological tissues were completely removed, and the walls of the cavity were treated with bone scrapers. The wound was tightly sutured, layerwise. The postoperative period was uneventful. Wound healing was by the first intention.

The bacteriological study of the surgical material involved inoculation for nonspecific microflora; the molecular, genetic, and cultural studies for Mycobacterium tuberculosis complex yielded negative results. According to the histological study of the surgical material, chondrosarcoma of the sternum was suspected; the diagnosis was confirmed during a review by oncomorphologists. Antitumor therapy was commenced in a specialized children’s oncology department of a federal research institute. However, at the age of 18 years, the patient was transferred under the supervision of the oncological service to a primary care facility; thus, follow-up was not possible.

Clinical case 2

Patient G., who was 12 years old, was admitted to the clinic with complaints of a tumor-like lesion with a purulent discharge in the sternum. Based on patient history, the lesion first appeared 6 months previously after trauma due to a fall from the height, but was not accompanied by local inflammatory phenomena. When the patient was presented at the hospital , the situation was considered a chest injury, and local treatment was performed with physiotherapy (high-frequency therapy No. 7) and application of anti-inflammatory ointments (non-steroidal anti-inflammatory drugs [NSAIDs], bepanthen, and akriderm) without positive changes. Later, there were periodic temperature rises, hyperemia, and local edema of the tissues in the area of the lesion. During a follow-up visit with the surgeon, a chest abscess was diagnosed; this was opened and drained. As per the description, pus and pathological masses regarded as “caseous” were obtained. According to the result of the cytological examination of a smear, no acid-fast bacteria were detected. A course of nonspecific antibacterial therapy (ceftriaxone, metragyl, amikacin, and gentamycin) was administered, during which a fistula with scanty mucous discharge was formed. Computed tomography of the thoracic organs revealed destruction in the manubrium and body of the sternum with a parasternal liquid component (Fig. 2) and infiltrative changes in segment 3 of the left lung (Fig. 3).

 

Fig. 2. Patient G., 12 years old. Computed tomography sections of the thorax (bone regimen): a – frontal, b – axial and c – sagittal. The arrows indicate the area of the sternum destruction

 

Fig. 3. Patient G., 12 years old. Computed tomograms of the chest (pulmonary regimen): a – frontal section, b – sagittal section, c – axial section. The arrows indicate the zone of infiltrative changes in the S3-segment on the left

 

The patient was hospitalized at the Saint-Petersburg State Research Institute of Phthisiopulmonology with suspected tuberculosis of the sternum. On examination, the pronounced edema was defined in the sternum on the left; the zone of hyperemia was up to 10 cm in diameter with a fistula of up to 1 cm in diameter in the center (Fig. 4) with the presence of scanty seropurulent discharge. The general blood test results revealed an increase in the number of leukocytes (15.3 × 109/L) without the formula shift, hemoglobin level of 103 g/L, and erythrocyte sedimentation rate of 46 mm/h. The biochemical blood analysis showed an increase in the C-reactive protein level up to 93.8 mg/L, while the fibrinogen level increased up to 5.312 g/L. Inoculation of the fistula discharge for nonspecific flora did not induce growth.

 

Fig. 4. Appearance of patient G., 12 years old: tumor-like lesion in the sternum with fistula

 

Fibrobronchoscopy: On the right, there was a compression stenosis of the middle lobe bronchus of the 1 deg. (up to 1/2 the diameter), mucosal edema. Inoculation of the swab for flora revealed no growth; no mycobacteria were detected on luminescent microscopy.

On December 27, 2016, surgery was performed in the volume of fistula-abscess-necrectomy as a therapeutic and diagnostic step, considering the prevalence of the lesion and its complications. At intervention, the subtotal destruction of the body and the manubrium of the sternum were revealed; the cartilaginous end of rib 3 was located freely; the parasternal pathological tissues contained liquid pus, granulation and necrotic detritus (Fig. 5, a). After necrectomy, the cavity dimensions were 100 × 40 × 30 mm, and the bottom of the cavity was the pericardium (Fig. 5, b). The wound was sutured under conditions of soft tissue deficiency with their tension; consequently, on post-op day 7, there was partial suture disruption with abundant serous discharge (sterile inoculation). During local treatment, second wound healing was achieved on postoperative day 20.

 

Fig. 5. Appearance of the surgical wound: a – cavity of destruction filled with granulation and necrotic tissue, b – appearance of cavity after osteonecrectomy. The bottom of the cavity (indicated by the arrow) is the pericardium

 

Bacteriological study of the surgical material for nonspecific microflora (inoculation) and for Mycobacterium tuberculosis complex (molecular and genetic study) yielded negative results.

Histological conclusion: “The material is represented as a tumor tissue consisting of large cells, including multinucleate cells, some with light cytoplasm; the bulk of the material is in the form of necrotic tissue, and the lymphoid tissue is practically absent” (Fig. 6).

 

Fig. 6. Morphological preparations (staining with hematoxylin and eosin, × 400): a, b – among the vast areas of necrosis (intermittent arrow) – Hodgkin and Reed-Sternberg giant multinucleate cells (solid arrows), lymphocytes, macrophages, and eosinophilic leukocytes

 

Immunohistochemical study results (Fig. 7) showed a positive reaction in the tumor on CD30, Pax5, and CD15 and negative reaction on CD45, CD20, CD3, CKAE1/AE3, CD1a, s100, myf4, and desmin. The Ki index was 67%–90%. Conclusion: Hodgkin’s lymphoma. The most probable nodular sclerosis NS2 (the material was subtotally necrotic).[1]

 

Fig. 7. Immunohistochemical study (IHC) of specimens of the patient G., 12 years old: a – expression of CD15 (occurs in Hodgkin’s disease, with some chronic B-lymphoblastic leukemias); b – CD30 expression (marker of Reed-Sternberg cells in Hodgkin’s lymphoma); c – reference IHC preparation in the classical version of Hodgkin’s lymphoma: tumor cells have phenotype of PAX 5+, CD45–, CD15+, and CD30+

 

The material was reviewed in three independent pathomorphological laboratories with coincidence of the conclusion. The patient was then transferred to the Department of chemotherapy of oncohematological diseases and bone marrow transplantation for children of the Almazov National Medical Research Centre where she is currently undergoing treatment.

Discussion

Attempts to compare our observations with the literature data proved to be challenging, primarily because because very few reports have been published on primary tumor lesions of the sternum in children owing to the rarity of this disease [2]. This was also challenging because in systemic lymphoproliferative diseases such as non-Hodgkin’s lymphoma and Hodgkin’s lymphoma [3-5], typically observed in this age group, the lesion of the sternum very rarely represents the main manifestation. However, it should be noted that that 0.2%-2% of all human malignant tumors are primary tumors of the thoracic wall. [6], and among all tumors of the sternum, 85% of the lesions are malignant, a considerable proportion of which are chondrosarcomas and malignant lymphomas [7-9].

Lack of specificity of the clinical manifestations of the sternum tumors, often absent or moderate pain syndrome, appearance of local hyperemia, and slowly progressing space-occupying lesions increasing to a significant size, together with the rarity of the pathology and the lack of sufficient awareness among doctors (pediatric surgeons and orthopedists) leads to late diagnoses and prolonged, inadequate treatment [2, 5, 10, 11]. Active surgical tactics have two principal advantages:

• The bacteriological study of the surgical material enables the exclusion of the infectious etiology of the process, and morphological study enables tumor verification. Thus, the presence of detritus that appears pathognomonic for a specific tuberculosis process should not lead to the abandonment of these studies. In the second observation, when pathological tissues were regarded as caseous and necrotic were detected, the doctors unreasonably abandoned these studies, leading to a delayed diagnosis of Hodgkin’s lymphoma.
• Early medical and diagnostic intervention with limited sternum destruction enables easier resolution and closure of the bone defect, while enhancing the restoration of the carcass of the chest, using different versions of grafting and metal osteosynthesis [8, 12, 13].

The experience of more than 100 surgeries performed on children with destructive lesions of the sternum in our clinic to date indicates that a large majority of them presented as infectious diseases, primarily tuberculous infections. Nevertheless, despite the extreme rarity of tumor lesions, oncological alertness is warranted in each case.

Conclusion

In our opinion, the clinical observations presented here are interesting from several points of view:

• The clinical and radiation picture of destructive lesions of the sternum has low specificity; thus, the diagnosis based on these data can only be considered preliminary, requiring further clarification.
• Complete bacteriological and morphological studies of the substrate from the bone destruction area should be performed as soon as possible to reduce the diagnostic delay and initiate appropriate, timely treatment.
• In the presence of destruction of the sternum in children, despite the overwhelming predominance of infectious (tuberculous) lesions, oncological alertness should always be present.

Information on funding and conflict of interest

The authors of the article declare no conflicts of interest.

The study received no external funding.

About the authors

Alexey S. Maletin

Saint-Petersburg State Research Institute of Phthisiopulmonology

Author for correspondence.
Email: maletin_aleksei@mail.ru

MD, children’s surgeon of pediatric surgery clinic

Russian Federation, 2-4, Ligovskiy pr., Saint-Petersburg, 191036

Vyacheslav I. Zorin

Saint-Petersburg State Research Institute of Phthisiopulmonology

Email: maletin_aleksei@mail.ru

MD, PhD, orthopedic and trauma surgeon of pediatric surgery clinic

Russian Federation, 2-4, Ligovskiy pr., Saint-Petersburg, 191036

Valeria A. Gileva

Saint-Petersburg State Research Institute of Phthisiopulmonology

Email: maletin_aleksei@mail.ru

MD, radiologist

Russian Federation, 2-4, Ligovskiy pr., Saint-Petersburg, 191036

Tatyana A. Novitsky

Saint-Petersburg State Research Institute of Phthisiopulmonology

Email: maletin_aleksei@mail.ru

MD, PhD, pathologist

Russian Federation, 2-4, Ligovskiy pr., Saint-Petersburg, 191036

Alexander Yu. Mushkin

Saint-Petersburg State Research Institute of Phthisiopulmonology

Email: maletin_aleksei@mail.ru

MD, PhD, professor, head of extrapulmonary tuber culosis department, head of pediatric surgery clinic

Russian Federation, 2-4, Ligovskiy pr., Saint-Petersburg, 191036

References

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