PET-CT Demonstration of Extensive Muscle Metastases From Breast Cancer

Subcutaneous and Muscle Metastases From Rectal Adenocarcinoma on 18 F-FDG PET/CT Imaging

ABSTRACT

A 50-year-old man with T4 N2 M1 poorly differentiated adenocarcinoma of the rectum underwent neoadjuvant chemotherapy, surgical resection, and subsequent chemotherapy. Six months after surgery, routine follow-up CT revealed the presence of abdominal wall subcutaneous nodules associated with bilateral pulmonary and renal nodules, indicating metastases. Further 18 F-FDG PET/CT scan revealed a high number of subcutaneous and muscle metastases. Metastasis of rectal adenocarcinoma to subcutaneous tissue or skeletal muscle is considered rare.

Prevalence, distribution, and clinical characteristics of hemangiosarcoma-associated skeletal muscle metastases in 61 dogs: A whole body computed tomographic study

BACKGROUND

Skeletal muscle metastases (SMMs) have been described sporadically in canine oncology.

HYPOTHESIS/OBJECTIVES

To determine the prevalence, localization, and clinical signs of SMMs associated with hemangiosarcoma (HSA) in a population of dogs presented for whole body computed tomography (CT).

ANIMALS

Dogs with a histologically confirmed HSA and a tissue core specimen or fine needle aspirate of suspected metastatic lesions were included in the study.

METHODS

Retrospective study. Dogs with a final diagnosis of visceral or muscular HSA that underwent whole body CT scan were enrolled in the study. Final diagnosis of primary tumor and SMMs was reached by histology, cytology, or both. Signalment, clinical signs, localization of the primary lesion, and metastases characteristics were reviewed.

RESULTS

Sixty-one dogs met the inclusion criteria. Skeletal muscle metastases were detected in 15 dogs (24.6%) and all of these dogs had also metastases in ≥1 sites. Presence of SMMs was significantly higher in males but was not significantly related to age, neuter status, breed, localization, and dimensions of the primary tumor. Nine of 15 (60.0%) dogs with SMMs showed lameness or reluctance to move whereas these signs were not recorded in any of the 42 dogs without SMMs (P < .001).

CONCLUSION AND CLINICAL IMPORTANCE

Prevalence of SMMs in our population of dogs with HSA was higher in comparison to previous studies in the human and veterinary medical literature. Whole body CT is recommended for staging of dogs with HSA, because SMMs could be missed by clinical examination and traditional diagnostic imaging modalities.

Metastatic breast cancer to the adductor magnus: A case report and literature overview

Metastatic breast cancer is commonly found in the pectoralis major and minor muscles, ribs, spine, pelvis, long bones of the extremities, liver, lung, and the brain. It is unusual to see breast cancer metastases to distal skeletal muscle. We report a case of a patient with a history of stage IIA infiltrating lobular carcinoma of the right breast presenting with a metastatic lesion in the right adductor magnus. She was treated four years prior to the onset of the metastases with a modified radical mastectomy but refused postoperative chemotherapy or adjunctive radiation.

Isolated Skeletal Muscle Metastasis and Hypercalcemia in Non-Small Cell Lung Carcinoma

Lung cancer is the most common malignancy throughout the world. Non-small cell lung carcinoma is the most common type and squamous cell type is the most common in India. Patients mostly present with chest related symptoms and signs. Isolated skeletal muscle metastasis (ISMM) is rarely seen. We describe a patient who presented with ISMM and hypercalcemia without any pulmonary symptoms.

Squamous Cell Carcinoma Lung with Skeletal Muscle Involvement: A 8-year Study of a Tertiary Care Hospital in Kashmir

Aims:

Lung cancer is the most common malignancy throughout the world. Nonsmall cell lung cancer (NSCLC) is the most common type, and squamous cell type is most common in India. Mostly, patients present with chest-related symptoms and signs. Isolated skeletal muscle metastasis (ISMM) is rarely seen. The aim was to see muscle metastasis and its prognosis.

Materials and Methods:

We are presenting our data of 8 years about this common malignancy with relation to muscle metastasis, either alone or with other system metastasis.

Results:

Muscle metastasis is seen 1.5% of patients, with male: female of 8:1. Overall median survival was 15 months and progression-free survival was 12 months.

Conclusion:

One peculiarity seen was ISMM with no pulmonary system and severe paraneoplastic hypercalcemia. Local therapy may be having an impact on overall survival in metachronous muscle involvement.

Infiltrative pattern of carcinomatosis in extremity muscles on MRI

Carcinomas can cause an unusual, infiltrative pattern of metastatic carcinoma in extremity muscles on MRI. To assess this pattern, reports of MRI exams of 907 consecutive patients with a diagnosis of carcinoma were reviewed retrospectively to identify those that mentioned muscle metastasis or myositis in an extremity. Thirty-six (4%) of those reports described muscle metastasis (n=18) or myositis (n=18); based on medical record review and imaging follow-up, 17 cases represented metastases. Metastases manifested as an infiltrative carcinomatosis pattern in five patients, resulted from primary esophageal or gastric adenocarcinomas, and often were misdiagnosed as myositis.

Detection of skeletal muscle metastasis: torso FDG PET-CT versus contrast-enhanced chest or abdomen CT

BACKGROUND

Skeletal muscle metastasis (SMM) in cancer patients has not been sufficiently evaluated regarding prevalence and proper method of detection.

PURPOSE

To determine the prevalence of SMM and compare the diagnostic competencies for SMM of torso F-18 fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) and contrast-enhanced chest or abdomen CT.

MATERIAL AND METHODS

We investigated 18,225 PET-CT studies of 6359 cancer patients performed from 2005 to 2012. The PET-CT studies describing potential SMM were retrieved and the corresponding medical records were reviewed. The gold standard for SMM was histopathologically-proven SMM or imaging study-based disease progression. The detectability of SMM was compared between PET-CT and contrast-enhanced CT.

RESULTS

Twenty-six patients had 84 SMM lesions, representing a SMM prevalence of 0.41%. Lung cancer was the most common SMM-associated malignancy (54%) and the gluteal/pelvic girdle muscle was the most frequently involved SMM site (37%). All 84 SMM lesions were visualized on PET-CT (100%). Of these PET-CT positive 84 SMM lesions, 51 lesions were in the CT field of view (FOV) (61%), whereas 33 lesions were out of the CT FOV (39%). Among these 51 lesions, 17 lesions showed rim-enhancing nodules/masses (33%), eight lesions showed homogeneously enhancing nodules (16%), three lesions showed heterogeneously enhancing nodules (6%), and 23 SMM lesions (45%) were non-diagnostic by CT. All 51 SMM lesions within CT FOV were detected on PET-CT (100%), whereas only 28 were visualized on CT (54.9%), resulting in a significant difference (P < 0.005). On average, 2.6 more organs with concomitant metastases were found when SMM was revealed by PET-CT.

CONCLUSION

The prevalence of SMM was as low as 0.41% in the current large cohort of cancer patients. Torso PET-CT was a more competent modality than contrast-enhanced CT in the detection of SMM.

PET/CT imaging of skeletal muscle metastases

BACKGROUND

Skeletal muscle metastases (SMM) are very rare because of complex resistance of the musculature to metastatic invasion. Previously, positron emission tomography (PET) imaging of SMM has been reported only in few reports. A systematic analysis of SMM features in PET/CT has not been performed before.

PURPOSE

To study PET/CT findings of SMM in a larger group of patients with known malignancies and to determine PET/CT patterns of SMM in different primary tumors.

MATERIAL AND METHODS

Between January 2009 and December 2011 581 patients with lung cancer were investigated by PET with 18 F-fluordeoxyglucose (FDG PET) and computed tomography (CT) at the Center of Fusion Imaging, Halle. In five patients SMM were identified. Furthermore, PubMed database was screened for muscle metastases. Only articles containing SUV of SMM were considered in the study. Twenty-one articles with 33 patients could be included in this meta-analysis from the literature.

RESULTS

At our center the prevalence of SMM was 0.9%. Our analysis comprised 38 patients with 67 muscle metastases. All identified SMM presented as intramuscular focal abnormal activity with SUV ranging from 2.4 to 25.9, median SUV 7.8. The median size of the muscle metastases was 2.5 cm (range, 0.6-6.5 cm). There were no significant differences between SUV and size of SMM arising from lung cancer, renal cell carcinoma, and esophageal cancer. Also, there was no correlation between SUV and size of SMM (r = 0.101, P = 0.558) and between SUV of SMM and primary tumors (r = 0.138, P = 0.686). In nine (23.7%) of the 38 patients, the identified SMM were isolated distant metastases or isolated tumor recurrence.

CONCLUSION

SMM manifested on PET/CT as focal hypermetabolic intramuscular areas with different SUV. There were no significant differences between SUV or size of the identified SMM in esophageal cancer, renal cell carcinoma, and lung cancer.

Intramuscular metastases on FDG PET-CT: a review of the literature

OBJECTIVE

Intramuscular metastases (IM) are both rare and difficult to detect using routine anatomical computed tomography (CT) imaging. However, since the introduction of 18F-fluoro-deoxy-glucose (FDG) PET-CT, the number of detected IM has increased. We review the available literature to illustrate the relevance of these findings for staging and patient management.

METHODS

In a review of the literature, we found one series and 33 case reports of IM shown on FDG PET-CT. No cases were reported before 2005. Furthermore, we present a patient with nonsmall cell lung cancer and a solitary distant metastasis in the left musculus infraspinatus that was not detected on diagnostic CT, but was found on FDG PET-CT.

RESULTS

For a total of 39 recorded cases of IM, we found that FDG PET-CT had a significant impact on patient management in at least 51% of cases. Where reported, lesions were either isodense or hypodense on CT compared with the surrounding muscle tissue. The lesions that were also analyzed with MRI showed heterogeneous intensity. Five out of 39 patients had metastases in the extraocular muscles of one or both orbits.

CONCLUSION

FDG PET-CT appears to be a sensitive tool for detecting IM, with important impact on management in many cases.

Metastatic breast carcinoma of the abdominal wall muscle: a case report

Metastasis from breast carcinoma is an uncommon occurrence in skeletal muscle, compared to local invasion into muscle from direct tumor spread. A 49-year-old woman was referred to our hospital with an 8.5-cm mass in the right breast. Core needle biopsy revealed metaplastic carcinoma with squamous metaplasia. The mass was rapidly growing and metaplastic, so mastectomy with dissection of axillary lymph nodes was performed. Pathological examination showed metaplastic carcinoma, histological grade 3, triple negative, and a MIB-1 labeling index of 80%. Six months postoperatively, during adjuvant chemotherapy treatment, she reported numbness and pain in the right lateral thigh and a mass in the right lower abdomen. Computed tomography revealed multiple lined masses in the abdominal wall and iliac muscle. Core needle biopsy showed metastatic breast carcinoma. Radio- and chemotherapy were administered, but the mass in the muscle became enlarged. To control her pain, a combined treatment with morphine, fentanyl, ketamine, antiepilepsy drug, and NSAIDs was administered. Liver metastasis appeared 9 months (15 months postoperatively) after recognition of muscle metastasis, and the patient died 16 months postoperatively. Skeletal muscle metastasis is uncommon, and therapeutic intervention is mainly palliative. The most common symptom of skeletal muscle metastasis is pain; thus, pain control is a pivotal goal of treatment.

Muscle metastasis of carcinoma

Metastatic carcinoma of the soft tissue is extremely rare compared with bone metastases. An intramuscular mass is often thought to be a primary soft tissue sarcoma because intramuscular metastases are very uncommon. Any painful soft tissue mass occurring in patients with a known history of carcinoma, particularly with extensive peritumoral enhancement associated with central necrosis, is highly suspicious for skeletal muscle metastasis. A needle biopsy is necessary for proper diagnosis. It is very important to make a differential diagnosis between metastasis and primary cancer in these cases. Here we present a review of known evidence.

Physiology and pathophysiology of incidental findings detected on FDG-PET scintigraphy

A routine feature of positron emission tomography/computed tomography (PET/CT) imaging is whole-body acquisition that results in many unexpected findings identified outside of the primary region of abnormality. Furthermore, (18)F-fluorodeoxyglucose (FDG) is a marker of glycolysis and does not specifically accumulate in malignancy. Understanding the physiology and pathophysiology of normal FDG distribution and common incidental findings is therefore essential to the physician interpreting whole-body FDG-PET/CT studies. Whereas many incidental findings are benign and of limited clinical significance, others represent uncommon manifestations of the primary malignancy, second malignancies, or various clinically significant pathologic processes. Patients with a single malignancy are at greater risk of developing synchronous or metachronous second malignancies, possibly related to exposure to shared carcinogenic agents or presence of prooncogenic mutations. The decision of how to pursue an intervention on the basis of an incidental finding is generally left to clinical judgment.

Skeletal muscle metastasis from non-small cell lung cancer

PURPOSE

Skeletal muscle metastases (SMM) from non-small cell lung cancer (NSCLC) are rarely encountered in clinical practice. The prognosis and the adequate treatment are not known. The aim of the study was to report our experience and to make an extensive literature research concerning SMM.

PATIENTS AND METHODS

In our unit, we identified 16 patients with SMM in a 10-year period. The source of our literature search (English and French language) was the international MEDLINE database, and it exhausted all cited publications.

RESULTS

We found 114 cases in the international literature (follow-up period mentioned in 72 cases). Pain was the most frequent symptom (83%). A mass was palpable in 78% of cases. The diagnosis was obtained by either fine needle/surgical biopsy or wide exeresis. The 5-year survival time was 11.5% with a median survival of 6 months. The 5-year survival rates: number of SMM - single versus multiple (13.6% [67 patients] versus 0% [21 patients]; p = 0.0022); disease-free interval (DFI) >6 months versus DFI < or =6 months (16.9% [18 patients] versus 9.1% [70 patients ]; p = 0.0458). We built three groups of prognostic significance: group I: DFI >6 months and single metastasis; group II: DFI >6 months or single metastasis; and group III: DFI < or =6 months and multiple metastasis. The 5-year survival rates were: group I (14 patients): group II (57 patients):group III (17 patients) = 28%:6%:0% (p = 0.0000), and the median survival was 19:9:4 months.

CONCLUSION

The presence of SMM suggests an aggressive disease. Selection of patients for a local treatment is an important factor that determines survival. The ideal patient had a unique metachronous metastasic deposit that can be treated by surgery.

Multiple metastases to skeletal muscle from carcinoma of the esophagus detected by FDG PET-CT imaging

A 67-year-old woman was treated with neoadjuvant chemotherapy, esophagectomy, and subsequent radiotherapy for T3N1 poorly differentiated adenocarcinoma of the esophagus. Five months after surgery, a routine follow-up CT demonstrated a 1.2-cm soft tissue mass in the posterior mediastinum suspicious for local recurrence. An FDG-PET/CT study confirmed tumor in the posterior mediastinum and also showed focal areas of increased tracer uptake within several muscles. Skeletal muscle is one of the most unusual sites of metastatic disease, although it is probable that the more frequent use of FDG-PET imaging will lead to an increase in the detection of such lesions.