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This digital library houses the book on Oncology and Orthopedic Oncosurgery.

It includes academic lectures, presentations from national and international congresses, published papers, case discussions, performed surgical procedures, and proprietary techniques developed.

The digital format was chosen because the web allows the inclusion of texts with numerous visual resources, such as images and videos, which would not be possible in a printed book.

The content is intended for students, healthcare professionals, and the general public interested in the field.

Diagnosis of bone lesions

Diagnosis of bone lesions

Figure 1: Bone neoplasms are divided into primary, which can be benign or malignant, and secondary, resulting from disease, radiation or metastases. In addition, there is a group of lesions that simulate bone tumors, such as simple bone cyst, aneurysmal bone cyst, cortical fibrous defect, eosinophilic granuloma, fibrous dysplasia and the brown tumor of hyperparathyroidism. To investigate the patient's diagnosis, it is essential to carry out a structured approach, which involves anamnesis and clinical examination, imaging tests such as radiography, computed tomography or magnetic resonance imaging, specific laboratory tests, biopsy for histopathological evaluation and vascular mapping and bone scintigraphy techniques to better understand the lesion
Figure 2: For the diagnosis of bone lesions, it is essential to maintain a balance between clinical evaluation, imaging, and pathology. Clinical assessment should be the foundation of this pyramid. Let’s analyze the case of a teenage girl presenting with alterations in the distal region of the thigh, where we observe edema, heat, pain, and a point of skin change. Could it be an insect bite? A hematoma? An infection? An open fracture from a puncture wound? Or are we dealing with a tumor? The imaging is aggressive, showing poorly defined borders, an intra- and extraosseous lesion, and a fine periosteal reaction in the metaphyseal region of the femur. These findings rule out other diagnostic possibilities and confirm the presence of a bone-forming tumor. The pathologist, upon examining the slide with anaplasia, hyperchromasia, atypical mitoses, and polymorphism of elongated cells, may interpret it as a fibrosarcoma. If we receive this diagnosis, we must question it by presenting the patient’s clinical and imaging findings to avoid another biopsy. Histology must identify newly formed bone to achieve a definitive diagnosis of fibroblastic osteosarcoma, ensuring the continuous balance between clinical evaluation, imaging, and pathology. Could it be a chondrosarcoma? We observe round and polymorphic cells, resembling chondroblasts. If newly formed bone is identified, the correct diagnosis will be chondroblastic osteosarcoma. Another slide may suggest an aneurysmal bone cyst, but the presence of newly formed bone confirms the diagnosis of telangiectatic osteosarcoma. Could it be an aggressive osteoblastoma? If the sample shows newly formed bone, the definitive diagnosis will be osteoblastic osteosarcoma. Thus, we conclude that biopsy should be the final procedure since osteosarcoma can present different histologies. Therefore, maintaining the correlation between clinical evaluation, imaging, and pathology in perfect balance is essential for an accurate diagnosis.
Figure 3: A biopsy is an essential procedure for confirming a diagnosis, complementing the information obtained from the clinic and imaging. We will discuss its concept, the different types of biopsies, their indications and the appropriate planning for their performance.
Figure 4: The purpose of the biopsy is to obtain a representative sample of the lesion, enabling histopathological analysis and an accurate diagnosis.
Figure 5: Types of biopsy include: Percutaneous biopsy, performed with needles, used when it is necessary to obtain samples for histopathological examination prior to treatment. Incisional biopsy, also known as open biopsy, used when it is essential to analyze part of the lesion in order to define the therapeutic approach. Excisional biopsy, in which complete resection of the lesion takes place, is indicated when the clinical and imaging findings are sufficient to allow definitive treatment.
Figure 6: Conditions that can be treated without a prior biopsy include osteoma, osteoid osteoma, osteochondromas and chondromas of the hands and feet. The latter can be approached surgically at a later stage, if necessary, due to the anatomy of the fingers as independent compartments. In addition, some bone lesions, such as chondroblastoma, simple bone cysts, juxta-articular bone cysts and cortical fibrous defects, can also do without a pre-surgical biopsy, as can certain soft tissue lesions.
Figure 7: Regarding the indication for biopsy, we begin by discussing a relevant clinical case. The hospitalized patient presented with a lesion in the abdominal wall, detected by tomography, showing a bulging projection of the rectus abdominis and transverse abdominal muscles. To properly analyze the origin of the lesion, we considered the major structures of the abdominal wall: - Skin (possibility of squamous cell carcinoma, basal cell carcinoma, or melanoma) - Subcutaneous tissue (lipoma, liposarcoma?) - Muscular fascia (desmoid fibroma) - Striated muscle (fibroma, fibrosarcoma, rhabdomyosarcoma) - Blood vessels (hemangioma, hemangiosarcoma) - Peritoneum and abdominal cavity (beyond our scope) Given the extent of the lesion, I suggested to the attending physician that they consult a specialized surgeon, as I would not be able to properly manage a malignant neoplasm. Ideally, the biopsy should be performed by the professional responsible for the patient’s future surgery. However, the physician insisted on conducting the biopsy, stating that the patient was jaundiced and had already undergone abdominal ultrasound and various laboratory tests. Upon questioning the physician about the patient's clinical history, I realized that no anamnesis had been performed. I then proposed a bedside visit to directly assess the patient. During the consultation, the patient reported having asthma and described the abrupt onset of symptoms following an episode of intense coughing that occurred eleven days earlier. Severe pain in the umbilical region was followed by significant initial bulging, which began to subside. Additionally, the lateral abdominal wall exhibited hardening. After clinical evaluation, I suggested that no biopsy be performed and that the patient be discharged, as the jaundice and elevated bilirubin levels were due to a large hematoma infiltrating the abdominal wall, caused by a spontaneous rupture of the anterior rectus abdominis muscle. The lesion was already in the process of healing, and a biopsy would only indicate an inflammatory condition in resolution, potentially leading to a histological diagnosis of proliferative myositis. In this case, the clinical history was crucial in determining the final diagnosis
Figure 8: After discharge, the patient returned to the clinic with residual ecchymosis from the hematoma, which, at rest, had accumulated on the flank of the abdomen. The clinical history was essential for the diagnosis, and simple clinical observation guided the treatment.
Figure 9: This case falls under the heading of clinical assessment and the importance of the physical examination in formulating the correct diagnosis. In the outpatient clinic, when considering the access route for the biopsy, the image analysis led to the need to question fundamental factors such as the patient's age and clinical history. The patient reported being 67 years old and had multiple lesions with destructive characteristics. Initial suspicions included metastases, myeloma or brown tumor from hyperparathyroidism. When I checked her medical records, I found records of pain in the ischial tuberosity, as well as laboratory tests and X-rays that had already been carried out. However, on examining the patient directly, it became clear that the lesion was not in the ischial tuberosity, but in the inguinal region anterior to the pelvis, indicating that she had not been properly examined. The correct diagnosis was an inguinocrural hernia, and the images of apparent bone rarefaction on the pelvic X-ray corresponded to superimposed intestinal gas. If a biopsy were to be carried out, there would be a risk of intestinal perforation. In this case, the physical examination was essential for an accurate diagnosis, avoiding an unnecessary and potentially harmful procedure.
Figure 10: Which chapter does this case fall under? The resident on duty in the emergency room comes to the bone tumor clinic and asks: "Doctor, what tumor does this patient seem to have? Can we schedule a biopsy?" As the doctor didn't know the patient's history, we went to the hospital's emergency room, where he reported that the symptoms started six months ago, with pain, heat and discharge. When the wound closed, he began to have a fever, swell up and the pain increased. Sometimes obtaining a medical history is a challenge, as the patient may hide or not provide complete information. We managed to get a confession that he had injured himself and bled a lot when jumping over a railing two years ago, but he didn't seek care for fear of being reported. First, it was necessary to reconstruct the clinical history. I then asked the resident to order a lateral X-ray, and to my astonishment, he hadn't requested it yet. The lateral X-ray revealed the presence of a foreign body. The spearhead of the metal fence had irritated the periosteum, generating a solid periosteal reaction and giving the false impression of a sclerotic tumor. In this case, proper imaging was essential for the diagnosis. Pathology cannot be a shortcut to diagnosis. It must always be correlated with clinical and imaging findings. After these three cases, we will study the controversial subject of biopsy.
Figure 11: CT scans showing an osteoma in the frontal region of the skull. No biopsy is indicated. Treatment can be observation only or resection if necessary due to aesthetic deformity.
Figure 12: Osteoma in the skull with painless bulging, causing difficulty combing the hair and aesthetic discomfort. Radiography reveals a homogeneous sclerotic lesion, characterizing an osteoma
Figure 13: Osteomas are well-defined, homogeneous and generally asymptomatic lesions. Sometimes they are occasional findings that appear on imaging tests, such as this osteoma of the femoral head, which does not require treatment. When they cause discomfort when putting on a glove, as in this phalangeal periosteoma, resection may be indicated. Excision should also be carried out when they occur, for example, in the nasal fossa, obstructing and making breathing difficult. This other osteoma, located on the forehead, makes it difficult to comb one's hair and causes significant aesthetic changes, indicating resection surgery without the need for a prior biopsy.
Figure 14: This lesion is located in the medullary region of the tibial metaphysis and is a Brodie abscess, which can be confused with an osteoid osteoma. Osteoid osteoma, however, has a different location, usually occurring in the densest region of the bone, which is the cortical bone. Despite the difference in location, the treatment is the same: excision of the lesion.
Figure 15: Osteoid osteoma, as we've already mentioned, is located in the cortex of long bones, or in the densest part of the affected bone. This case is an example of an osteoid osteoma affecting the cortex of the diaphysis of the tibia. If you need any help, I'm happy to help!
Figure 16: Osteoid osteoma in the vertebral pedicle, which is the densest region of the vertebra, and in the calcar of the femur, the cortical region. There is no indication for a biopsy prior to treatment.
Figure 17: Subtalar osteoid osteoma, located in the densest region of the calcaneus, the sustentaculum tali. There is no indication for a biopsy prior to treatment.
Figure 18: As for osteochondromas, such as this pedicled one in the femur or tibia, there is no indication for a biopsy. The radiographic characteristics of osteochondromas show that the cortical bone continues with the cortical bone of the lesion, just as the medullary bone continues with the medullary bone of the lesion.
Figure 19: Hereditary multiple osteochondromatosis. Multiple lesions in siblings, highlighted by the white, yellow and blue arrows. There are deformities in the limbs which, fortunately, grow symmetrically with little angular change.
Figure 20: Chondromas in the phalanges, identified during the investigation of deformities, which are generally asymptomatic and whose initial approach may be observation only. If a biopsy is carried out, the histology found will be similar to this image, showing mature cartilage.
Figure 21: Chondroma with insufflations and thinning of the cortex, resulting in pain and discomfort. Curettage is indicated, and thermocauterization and autologous grafting can be added if necessary.
Figure 22: Dorsal access, careful curettage of the lesion and autologous iliac bone graft to fill the cavity. In the fingers and toes, cartilaginous lesions generally present benign behavior. If there is an unwanted development into a chondrosarcoma after curettage surgery in these locations, this does not compromise the possibility of a cure, as complete resection of the finger - which is the treatment for chondrosarcoma - would still be feasible.
Figure 23: Epiphyseal lesion of bone rarefaction in a child, on a growing skeleton, with a halo of sclerosis showing precise limits, indicating benignity, and foci of calcification, often seen in cartilaginous lesions. This image is characteristic of a chondroblastoma, which can be treated surgically without the need for a prior biopsy.
Figure 24: Simple bone cyst of the humerus, a common lesion in childhood and adolescence, preferentially located in the metaphysis. The clinical picture includes swelling and pain due to microfracture, at which point it is usually diagnosed and can progress to healing. The lesion is well delimited and does not extend beyond the width of the metaphysis. As the child develops, the cystic cavity can move away from the growth plate and be located in the diaphysis. It is a single cavity, lined with membrane and containing serous fluid, and clinical and imaging findings are sufficient for diagnosis and treatment. No prior biopsy is indicated.
Figure 25: Simple bone cyst in the fibula. This is the only location where the simple bone cyst may be wider than the metaphysis, due to inflation of the cortical bone, which is thin in this location. As it is not a load-bearing bone, observation may be the best course of action. As the child develops, the cyst moves away from the epiphyseal line and can mineralize, evolving towards healing, as this case demonstrates.
Figure 26: Simple bone cyst in the tibia. Pain caused by traction of the patellar ligament on the anterior tibial tuberosity, resulting from thinning of the cortical bone due to growth of the cyst.
Figure 27: MRI complements the imaging study, revealing a single, well-defined cavity with liquid content surrounded by a membrane, highlighted by the red arrow. The membrane only picks up contrast on the periphery of the lesion. Treatment does not require prior biopsy.
Figure 28: The ganglion is an epiphyseal lesion with bony rarefaction, well delimited. This MRI shows the perforation in the articular cartilage, allowing communication between the joint fluid and the contents of the cavity. The ganglion is also known as a juxta-articular bone cyst.
Figure 29: X-ray showing a circumscribed lesion in the cortex of the femur. The CT scan shows that it is homogeneous, small, less than 1.5 cm, delimited by a halo of sclerosis. Cortical fibrous defect operated on due to mild discomfort caused by traction on the insertion of the tendon of the adductor longus muscle.
Figure 30: Pain in the medial aspect of the left thigh eight months ago, after trauma. Hypotrophy of the quadriceps, showing chronic injury. The pain was more intense in the distal region of the thigh. Scintigraphy revealed contrast uptake and radiography showed ossification in the soft tissues, at the point of greatest pain, pointing to the diagnosis of myositis ossificans. Clinical, imaging and laboratory tests are decisive for the diagnosis of myositis ossificans
Figure 31: Tomography and MRI confirming ossification in soft tissues, predominantly in the periphery of the lesion. Biopsy may result in a false diagnosis of osteosarcoma! The best course of action in this case is to take the data obtained at face value, carry out Ca++, P++ and alkaline phosphatase tests and wait for the process to mature before surgical intervention. Intervening while AF is altered could trigger a significant increase in ossification, making surgery more difficult and complicating treatment. The clinical history and laboratory and imaging tests are sufficient to define the course of action.
Figure 32: Soft tissue tumor in the gluteal region, homogeneous, with fat density on T1, accompanying the appearance of fat on the image with saturation. This is a lipoma, which does not require a biopsy prior to resection, if surgery is the chosen option.
Figure 33: MRI scan confirming homogeneous fatty tissue, with contrast uptake restricted to the periphery of the tumor. Resection of the lipoma wrapped in its pseudocapsule. LIPOMA.
Figure 34: MRI scan of the forearm showing a soft tissue lesion in the path of the posterior interosseous nerve. The clinic reveals a positive Tinel's sign in the path of the nerve, confirming the diagnosis of SCHWANNOMA. The recommended course of action is resection with biopsy, gently opening the perineurium and enucleating the tumor, which detaches easily, like removing an avocado pit.
Figure 35: Another case in which the X-ray reveals a tumor in the popliteal cavus. MRI scans in T1 and T2 delineate the “comet tail” in the path of the sciatic nerve. Treatment consists of excising the lesion, which resembles an onion. The sheath is carefully opened and the lesion is removed completely, without damaging the nerve. Biopsy is even contraindicated, as it would remove a fragment of the nerve and could cause neurological deficit
Figure 36: When biopsy is necessary for treatment, there are some fundamental precautions to be observed: - The surgeon responsible for the treatment must monitor the procedure, ensuring that it is carried out according to the surgical plan. - Avoid transverse incisions, which can compromise the definitive approach. - Do not make extensive incisions in areas without sufficient musculature, such as the leg, where posterior coverage may be difficult. - Be careful when suturing: the stitches should not be far from the incision, as this may require a wider resection of the tissue. - Avoid multiple incisions, as illustrated in this chart with three different routes, to minimize damage and facilitate reconstruction.
Figure 37: Another iatrogeny: two distant incisions, with a subcutaneous nodule indicating the implantation of a giant cell tumor! Inadequate biopsy can lead to dissemination of the lesion and complicate treatment. This case highlights the importance of careful surgical planning, minimizing risks and ensuring the best therapeutic approach.
Figure 38: Unfortunately, another case of multiple incisions in a malignant neoplasm, making it difficult to resect this chondrosarcoma with an adequate margin. In view of the inadequate pathways, it was necessary to perform an extra-articular resection and reconstruction using a knee arthrodesis. To avoid amputation of the thigh, a custom-made rigid prosthesis was used, ensuring the best possible approach.
Figure 39: Biopsy performed with a transverse incision, an inappropriate route that makes it difficult to resect this chondrosarcoma of the pelvis with an adequate margin. This inappropriate approach made it necessary to perform a wide skin resection for the internal hemipelvectomy, allowing complete removal of the biopsy tract
Figure 40: This case exemplifies a correctly performed biopsy on a Ewing's sarcoma of the proximal tibia, allowing complete resection of the path through the surgical incision. Performing the biopsy properly is essential to facilitate treatment planning and ensure adequate resection margins, avoiding additional complications.
Figure 41: Case of osteosarcoma in the posteromedial region of the tibia. The arrow indicates the correct point for collecting the biopsy, which should be carried out in the path of the future surgical incision, ensuring that complete resection of the lesion can be carried out without compromising adjacent structures.
Figure 42: Punctate biopsy scar performed correctly, ensuring that the tumor is resected with an adequate margin, including the biopsy path. Precision in performing the biopsy is essential to facilitate definitive treatment and avoid complications in the surgical approach.
Figure 43: To plan the biopsy in this first case, with a lesion of bone rarefaction with imprecise boundaries, aggressive and with foci of calcification, some points should be considered: - Collection site: The biopsy should be carried out in the most representative region of the lesion, avoiding areas of necrosis, if present. - Incision route: Access should be planned along the route of the future surgical incision, ensuring that the entire biopsy route is subsequently resected. - Type of biopsy: An incisional biopsy can be performed if the definitive surgical approach has not yet been defined, or a needle biopsy if sufficient material can be obtained for histological analysis. - Technical precautions: Avoid transverse routes and multiple incisions. It is essential that the procedure is accompanied by the surgeon responsible for the definitive treatment
Figure 44: This lesion affects the entire right iliac wing, extending down the posterior column and reaching the supra-acetabular region.
Figure 45: How should we plan the surgical incision for a future oncological resection, in the most functional way possible, in this case of an aggressive tumor, eroding the entire iliac wing, also reaching the extra-bone space, and spilling over the external and internal plate of the right pelvis?
Figure 46: We can see that the extraosseous lesion is delimited internally by the peritoneum (red arrow), externally by the gluteus muscle (yellow arrow) and covered by the fat plane (white arrow). The ideal route for the biopsy should be through the iliac crest (blue arrow). In this way, surgical access will be possible: - Internally: follow the detachment of the peritoneum. - Externally: resect a strip of the gluteal muscle, which will serve as the boundary of the tumor, guaranteeing a resection with an oncological margin. In this way, we will preserve as much of the musculature as possible, guaranteeing adequate coverage of the surgical wound and maintaining maximum motor function.
Figure 47: Upon entering the CT room, the patient was already anesthetized and positioned prone!!! When I questioned the radiologist, he replied that this was the best position to easily obtain the sample!!! I drew the path of the planned incision and asked him to mark the point where he wanted to puncture the biopsy. He marked it with an “X”. - I explained to him that the puncture on the gluteus would be outside the planned surgical path, implying the resection of a significant part of this musculature, which would compromise function and make the resection more difficult. - After analyzing the CT scan, he understood the need to change the puncture site. - He chose to perform the biopsy on the iliac crest laterally, respecting the surgical plan. - This diagram describes the intended future resection, with an oncological margin and tissue preservation.
Figure 48: The biopsy was carried out under sedation and image control, following the route appropriate to our planning. The material collected must be analyzed immediately by the pathologist, who is present when the sample is taken. This procedure is known as a “frozen” biopsy, in which the pathologist does not state the diagnosis at this point, as the bone material needs to be decalcified and then embedded in paraffin, allowing the slide to be stained and read histologically. The participation of the pathologist at this stage is essential to ensure that: - The sample taken is representative of the lesion. - The material collected is sufficient for immunohistochemical study.
Figure 49: During surgery, the patient is positioned in the lateral decubitus position and the path of the surgical incision is marked on the skin, including the resection of the area where the biopsy was taken. We can see that the incision allows the tumor to be resected with a monobloc oncological margin, together with the biopsy area.
Figure 50: This aggressive lesion in the metaphysis of the femur, with major extra-cortical involvement - anteriorly, laterally and posteriorly - should not be biopsied through the vastus lateralis muscle, as this route is inadequate and would result in muscle damage, making partial resection of the motor unit necessary, which would compromise both coverage and functional recovery. The correct access is to perform the procedure through the intermuscular septum, sampling the posterior extra-cortical material, without the need to perforate the cortex to obtain the sample.
Figure 51: With the patient in prone position, we have the ideal position to facilitate the biopsy. The yellow arrow highlights the entry point and the direction of the needle. The tomographic control allows us to monitor and document the taking of the sample for histological analysis, acquired through the intermuscular septum.

Case Author

Author: Prof. Dr. Pedro Péricles Ribeiro Baptista

 Orthopedic Oncosurgery at the Dr. Arnaldo Vieira de Carvalho Cancer Institute

Office :  Rua General Jardim, 846 – Cj 41 – Cep: 01223-010 Higienópolis São Paulo – SP

Phone: +55 11 3231-4638  Cell:+55  11 99863-5577   Email:  drpprb@gmail.com

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