Figure 1
Radiography of the Proximal Femur
Anteroposterior radiograph of proximal right femur shows an ill-defined area of mildly sclerotic medulla (arrowheads), without cortical or periosteal involvement.
Clinical History
Patient with known and treated bronchial carcinoid who presented with increasing pain involving the right upper thigh.
Imaging Findings
The patient is a 71-year-old male with known and treated bronchial carcinoid who presented with increasing pain involving the right upper thigh. Radiography (Fig. 1a) was obtained, followed by lower extremity MR imaging (Figs. 1b-1c).
Radiography of the proximal right femur showed an ill-defined area of increased density in the medullary space, without apparent cortical or periosteal involvement. MR imaging showed a low T1 signal and high T2 signal mass with well-defined margins and periosteal reaction indicating an aggressive process. The clinical suspicion for metastatic carcinoid was high and confirmed at biopsy (Fig. 1d).
Radiography of the proximal right femur showed an ill-defined area of increased density in the medullary space, without apparent cortical or periosteal involvement. MR imaging showed a low T1 signal and high T2 signal mass with well-defined margins and periosteal reaction indicating an aggressive process. The clinical suspicion for metastatic carcinoid was high and confirmed at biopsy (Fig. 1d).
Discussion
Carcinoid is a neuroendocrine tumor that arises from enterochromaffin cells of the alimentary tract. This malignancy is classified based upon its embryonic origin, and may involve the foregut, lungs, bronchi, midgut, and hindgut [1]. Histologically, carcinoid tumor cells appear in clusters surrounded by fibrous strands, with large, uniform, hyperchromatic nuclei and eosinophilic cytoplasm [2]. Bronchial and gastrointestinal carcinoids are histologically distinguished by the presence of argentaffin and argyrophil granules, which are present in gastrointestinal carcinoid and rarely seen in bronchial carcinoid [3]. Histologic features do not determine malignant potential [4].
The majority of patients with carcinoid tumors are asymptomatic and diagnosed incidentally. Symptoms are usually related to the location of the tumor, with the exception being patients that develop carcinoid syndrome. The syndrome occurs in a small number of patients, with 90% of cases demonstrating metastatic involvement of the liver. These patients classically present with systemic effects, which include skin flushing, diarrhea, and cyanosis, caused by the vasoactive amines secreted by carcinoid cells. Approximately 10% of carcinoids metastasize, which may occur as late as 20 years following initial resection of the primary tumor [3].
Metastases to bone are more frequently associated with bronchial as opposed to gastrointestinal carcinoid. Bone metastases typically involve the axial skeleton and are usually osteoblastic in nature. On radiographs, osteoblastic lesions of carcinoid metastases are indistinguishable from prostatic metastases and chronic sclerosing osteomyelitis [1]. Solitary sclerotic lesions with periosteal reaction in a sunburst pattern, an appearance similar to osteosarcoma, have been reported in carcinoid metastases [3]. Osteolytic lesions may also be seen, but in these cases the carcinoid is more likely to be of gastrointestinal origin [2]. Skeletal scintigraphy typically shows increased radiopharmaceutical uptake.
The treatment of choice for primary bronchial carcinoid is resection, which offers an excellent prognosis due to the slow growth of carcinoid tumors. Bony metastases are most commonly treated with external radiation therapy; the primary goal is symptom relief. Metastatic disease is generally indolent, with some patient survival reports showing survival greater than 10 years from the initial diagnosis of metastatic disease [1].
The majority of patients with carcinoid tumors are asymptomatic and diagnosed incidentally. Symptoms are usually related to the location of the tumor, with the exception being patients that develop carcinoid syndrome. The syndrome occurs in a small number of patients, with 90% of cases demonstrating metastatic involvement of the liver. These patients classically present with systemic effects, which include skin flushing, diarrhea, and cyanosis, caused by the vasoactive amines secreted by carcinoid cells. Approximately 10% of carcinoids metastasize, which may occur as late as 20 years following initial resection of the primary tumor [3].
Metastases to bone are more frequently associated with bronchial as opposed to gastrointestinal carcinoid. Bone metastases typically involve the axial skeleton and are usually osteoblastic in nature. On radiographs, osteoblastic lesions of carcinoid metastases are indistinguishable from prostatic metastases and chronic sclerosing osteomyelitis [1]. Solitary sclerotic lesions with periosteal reaction in a sunburst pattern, an appearance similar to osteosarcoma, have been reported in carcinoid metastases [3]. Osteolytic lesions may also be seen, but in these cases the carcinoid is more likely to be of gastrointestinal origin [2]. Skeletal scintigraphy typically shows increased radiopharmaceutical uptake.
The treatment of choice for primary bronchial carcinoid is resection, which offers an excellent prognosis due to the slow growth of carcinoid tumors. Bony metastases are most commonly treated with external radiation therapy; the primary goal is symptom relief. Metastatic disease is generally indolent, with some patient survival reports showing survival greater than 10 years from the initial diagnosis of metastatic disease [1].
Differential Diagnosis List
Carcinoid Tumor Metastatic to the Femur
Final Diagnosis
Carcinoid Tumor Metastatic to the Femur
References
[1]
Metastatic carcinoid of bone.
Report of two cases and review of the literature.
Clin Orthop. 1988;230:266-72. Review. (PMID: 3284679)
[2] Kaplan PA, Phalen J, Macke R. <br>Case report 372: Bronchial carcinoid metastatic to bone, specifically involving the left femur. <br>Skeletal Radiol 1986;15(5):383-6.
[3]
Johnson DG, Osborne D, Bossen EH.
Case report 185: metastasis to the femur from a bronchial carcinoid tumor.
Skeletal Radiol. 1982;7:293-295. (PMID: 7071630)
[4]
Desai SP, Yuille DL.
Visualization of a recurrent carcinoid tumor and an occult distant metastasis by technetium-99-sestamibi.
J Nucl Med 1993;34:1748-1751. (PMID: 8410293)
Case information
| URL: | https://eurorad.org/case/2291 |
| DOI: | 10.1594/EURORAD/CASE.2291 |
| ISSN: | 1563-4086 |
Figure 2
MRI Hip
Coronal spin-echo T1-weighted MR image shows a 6.8 cm long, circumscribed, hypointense mass involving the proximal right femur. There is a small amount of edema surrounding the mass.
Axial fat-suppressed, fast spin-echo T2-weighted MR image demonstrates a heterogeneous yet predominantly hyperintense mass without cortical destruction. Periosteal reaction is identified anteriorly and there is a mild amount of edema surrounding the cortex.
Radiography of the Proximal Femur
Anteroposterior radiograph of proximal right femur shows an ill-defined area of mildly sclerotic medulla (arrowheads), without cortical or periosteal involvement.
MRI Hip
Coronal spin-echo T1-weighted MR image shows a 6.8 cm long, circumscribed, hypointense mass involving the proximal right femur. There is a small amount of edema surrounding the mass.
Axial fat-suppressed, fast spin-echo T2-weighted MR image demonstrates a heterogeneous yet predominantly hyperintense mass without cortical destruction. Periosteal reaction is identified anteriorly and there is a mild amount of edema surrounding the cortex.