Metastatic Bladder Urothelial Carcinoma Masquerading as Myositis.

Skeletal muscle metastases are uncommon, and metastases of urothelial carcinoma to the skeletal muscle are particularly rare. The most common presentation of skeletal muscle metastases is a focal mass, but their clinical and radiographic findings can be diverse. We present an unusual case of a 71-year-old male without prior known history of malignancy who presented with skeletal muscle pain with imaging most consistent with an inflammatory or infectious process but was ultimately determined to be metastatic urothelial carcinoma from the bladder. This case demonstrates the need to keep an expanded differential for muscular pain, particularly when initial treatments are ineffective.

Upper Tract Urothelial Carcinoma Complicated by Skeletal Muscle Metastases.

Urothelial carcinoma typically metastasizes via a lymphatic route to sites such as lymph nodes, bone, and liver. As in other malignancies, metastasis to skeletal muscle is rare. We present a case of a 66-year-old male with severe muscular pain after diagnosis of upper tract urothelial carcinoma, who was found to have extensive metastasis to skeletal muscles including gluteal, sternocleidomastoid, deltoid, vastus lateralis, and gastrocnemius muscles. Literature review demonstrated 18 previously reported cases of urothelial cell carcinoma with skeletal muscle metastasis, all male and all with bladder involvement. This case emphasizes the importance of thoroughly evaluating all muscular pain in patients with a history of malignancy as it may represent skeletal muscle metastasis with an associated increase in morbidity and mortality.

Necrotizing Pneumonia, a Skeletal Muscle Lesion, and a Fungating Duodenal Mass: An Atypical Presentation of Rapidly Progressing Lung Adenocarcinoma.

Lung adenocarcinoma, the predominant subtype of non-small cell lung cancer, typically metastasizes to common sites such as the liver and adrenal glands. However, rare instances involve skeletal muscle metastasis. We present a case of a 45-year-old female with a medical history of hypertension, epilepsy, and fibromyalgia, who presented to the emergency department with hemoptysis and multifocal pain. Chest imaging revealed a cavitary lesion which appeared to be necrotizing pneumonia. Further investigations uncovered a fluid collection in the left thigh, which would be identified as poorly differentiated carcinoma. Subsequent testing identified the lung as the primary source of metastasis. Despite radiation treatment, the patient's condition deteriorated over the next 50 days, highlighting the aggressive nature of the disease.

Primary rectal adenocarcinoma with musculoskeletal metastasis as the only metastasis site: A case report with a short literature review.

Rectal carcinoma with metastasis to skeletal muscle is a rare occurrence. Since 1970, only 30 cases of skeletal muscle metastasis originating from colorectal adenocarcinomas have been documented, underscoring its exceptionally low incidence. Here, we present the case of a middle-aged man who was diagnosed with rectal adenocarcinoma 3 months ago. During examination, a subcutaneous mass was discovered in the left proximal buttock. Histological analysis of a biopsy confirmed that this mass was a metastatic lesion originating from the primary rectal adenocarcinoma.

Extensive Skeletal Muscle Metastases in Malignant Pleural Mesothelioma Detected by FDG PET/CT.

Malignant pleural mesothelioma (MPM) is a rare but aggressive tumor originating from pleural mesothelial cells. Distant skeletal muscle metastasis is rare in MPM. A 54-year-old woman was diagnosed with epithelioid MPM and treated with surgery, chemotherapy, and radiotherapy 2 years ago. During follow-up, diffuse irregular pleural thickening with focal chest wall invasion in the right hemithorax and two small pleural thickenings in the left hemithorax were seen on control diagnostic contrast-enhanced computed tomography (CECT). Fluorine-18 fluorodeoxyglucose positron emission tomography/CT (FDG PET/CT) imaging was performed as part of restaging. PET showed diffusely increased FDG uptake in the recurrent right pleural tumor, and two hypermetabolic small metastatic foci in the contralateral pleura. In addition, multiple hypermetabolic areas of various sizes in various skeletal muscle localizations, suggestive of extensive muscle metastases were noted. Histopathologic study confirmed metastatic epithelioid MPM. FDG PET/CT revealed multiple muscle metastases which were not observed on earlier CECT and contributed to the visualization of more extensive metastatic involvements in the presented case with MPM. FDG PET/CT can detect rarely seen skeletal muscle metastases that are not visualized on diagnostic CT, and provides more accurate restaging of MPM.

Multifocal Ectopic Recurrence of a C2 Chordoma.

Background Chordomas are histologically benign but locally aggressive tumors with a high propensity to recur. Our case highlights the importance of long-term vigilance in patients who have undergone chordoma resection. Case Report We report the case of a 47-year-old man with a cervical chordoma who developed multiple musculoskeletal ectopic recurrences in the left supraclavicular region, the proximal right bicep, and the left submandibular region without recurrence in the primary tumor site. Primary tumor resection was achieved via a combination of surgery, adjuvant radiation therapy, and imatinib. All recurrences were successfully resected and confirmed via pathology to be ectopic chordoma. Discussion Ectopic recurrence of cervical chordoma is rare and lung is the most common site of distant spread. Chordoma recurrence in skeletal muscle is particularly rare, with only 10 cases described in the literature. A plausible mechanism of distant metastatic disease in chordoma patients suggests that tumor cells escape the surgical tract via a combination of cytokine release, vasodilation, and microtrauma induced during resection. Conclusion Cervical chordoma with ectopic recurrence in skeletal muscle has not been previously described in the literature. Skull base surgeons should be aware of the phenomenon of chordoma ectopic recurrence in the absence of local recurrence.

Soft Tissue and Lower Limb Muscle Metastases from Breast Carcinoma: An Unreported Entity.

Soft tissue metastasis from carcinoma breast is rare, and still rarer is metastasis to skeletal muscles. So far, soft tissue metastasis from breast carcinoma has been reported only in a small number of case series and case reports. To the best of our knowledge, no case of breast cancer metastasizing to the lower limb muscles has been reported. It is important to differentiate soft tissue metastasis from primary soft tissue malignancy, as the management and prognosis of these differ markedly. Here, we present a case of breast cancer metastasizing to the soft tissue at multiple sites including the right thigh muscles.

A Rare Case of Abdominal Wall Skeletal Muscle Metastasis From Adenocarcinoma of the Pancreatic Head.

Pancreatic cancer can be aggressive and commonly metastasizes to various organs. Most commonly, pancreatic cancer metastasizes to the lung, liver, bones, and peritoneum, but very rarely does it spread to the abdominal wall or skeletal muscle. In this case, we discuss a patient who initially presented with weight loss and jaundice from a pancreatic head adenocarcinoma that later metastasized to the rectus abdominis muscle. A 63-year-old female presented with jaundice and weight loss. CT imaging revealed a 2.8 cm pancreatic head mass with pancreatic and biliary ductal dilation. Carbohydrate antigen 19-9 (CA 19-9) level was also found to be elevated to 1810 U/mL. An endoscopic ultrasound-guided biopsy was later performed and confirmed pancreatic adenocarcinoma. The patient underwent a Whipple pancreatoduodenectomy following initial treatment with neoadjuvant FOLFIRINOX chemotherapy. Following the Whipple procedure, she received adjuvant chemotherapy and subsequent imaging revealed no recurrence and decreased CA 19-9 level to 46 U/mL. Eight months afterward, the patient presented once again with lower abdominal pain. Repeat CA 19-9 level was found to have increased to 1503 U/mL. Repeat positron emission tomography scan imaging was performed and showed a 4.7 cm left rectus abdominis muscle mass. The mass was later biopsied, and pathology revealed recurrent, metastatic pancreatic adenocarcinoma. The patient was restarted on chemotherapy with paclitaxel and gemcitabine leading to a reduction in tumor size and CA 19-9 levels of 135 U/mL. However, surgical resection was later pursued due to increased tumor size only four months later. At this time, limited literature is available reporting the occurrence of pancreatic cancer metastasizing to the abdominal wall. Upon literature review, only five cases have been reported to date, and only two of the cases involved the skeletal muscle. Our rare case is the first-time documentation of rectus abdominis metastasis from pancreatic adenocarcinoma arising from the pancreatic head.

Case report: skeletal muscle metastasis from follicular thyroid carcinoma presenting as synovial sarcoma.

Differentiated thyroid carcinomas tend to remain localized and usually are of slow progression with excellent long-term survival. The major sites of distant metastases are cervical lymph nodes, lungs and bones and the minor sites include the brain, liver, pericardium, skin, kidney, pleura and muscle. Skeletal muscle metastases from differentiated thyroid carcinoma, are exceedingly rare. In this report, a 42-year-old woman with follicular thyroid cancer that had had a total thyroidectomy and radioiodine ablation nine years ago was presented with a painful right thigh mass and negative PET/CT scan. The patient had also lung metastases during the follow-up period which were treated with surgery, chemotherapy and radiation therapy. An MRI scan of the right thigh showed a deep-seated lobulated mass with cystic regions, bleeding elements and strong heterogeneous post contrast administration enhancement. Due to the similarities in clinical manifestations and imaging features between soft tissue tumors and skeletal muscle metastases, the case was initially misdiagnosed in favor of synovial sarcoma. Histopathological, immunohistochemistry and molecular analysis of the soft tissue mass confirmed to be a thyroid metastasis and, as a result, a final diagnosis of skeletal muscle metastasis was provided. Even though the probability of a skeletal muscle metastasis from thyroid cancer approaches zero, this study aims to raise the awareness to the medical community that these events do in fact occur in the clinical setting and should be considered in the differential diagnosis of patients with thyroid carcinomas.

Pancreatic Cancer with a Skeletal Muscle Metastasis-A Case Presentation and Literature Review.

One-half of patients with newly diagnosed pancreatic cancer will have metastatic disease at the time of diagnosis, mainly due to its non-specific initial clinical presentation which includes abdominal pain, dyspepsia, weight loss, bowel habit changes, jaundice and pruritus. The signs, symptoms and stage of the disease at initial diagnosis depends on the origin of the primary tumor, with tumors of the head presenting earlier with obstructive symptoms while tumors of the body/tail are often diagnosed at an advanced stage due to their non-specific presentation. The most common sites of metastasis are the lymph nodes, liver, lung, and peritoneum. The presence of metastatic disease in the skeletal muscles is a rare manifestation of pancreatic cancer and has been described in a limited number of cases. We report the case of a pancreatic cancer patient with a solitary muscle lesion as the only site of extra-nodal metastasis upon initial presentation.

Skeletal muscle metastasis from extrahepatic cholangiocarcinoma: A case report and literature review.

Background: Cholangiocarcinoma (CCA) is a type of malignant tumor that arises from the epithelium of the bile ducts. According to anatomical location, CCA can be classified as intrahepatic (ICC), perihilar (PCC), or extrahepatic (ECC). CCA can invade and metastasize to other tissues in various ways, but distal skeletal muscle metastasis (SMM) is extremely rare. There are several reports on SMM from ICC or PCC, but SMM from ECC has not yet been reported. Case presentation: A 71-year-old woman was diagnosed with ECC, for which she underwent pancreatoduodenectomy and partial hepatectomy. Nine months after surgery, she was re-admitted to the hospital complaining of a rapidly growing mass on her right thigh with progressive lower extremity edema. Magnetic resonance imaging of the right thigh showed two masses with iso-signal intensity on T1-weighted images and hyper-intensity on T2-weighted images compared with the surrounding muscles. Pathological examination of the fine-needle biopsy specimen revealed that it was similar to the previously detected ECC, and the diagnosis was metastasis of ECC. The patient was treated with opioid analgesics and died of systemic failure three months later. Conclusion: SMM should be considered during the follow-up period despite its low incidence, and perineural invasion may be an essential pathway of distant metastasis in CCA.

Triceps mass - A rare presentation of renal cell carcinoma.

Renal cell carcinoma (RCC) can commonly metastasize to the liver, lungs, bones and brain. We herein report a rare presentation of oligometastatic RCC with isolated synchronous metastasis to the triceps. A 44-year-old male presented with an enlarging mass involving the right triceps. A biopsy revealed features consistent with metastatic clear cell RCC (ccRCC). Subsequent computed tomography (CT) Imaging demonstrated a 6 cm right renal mass. He underwent a right laparoscopic radical nephrectomy which revealed a tumour stage 1b ISUP Grade 2 ccRCC. Clinicians should have a degree of suspicion for a metastatic lesion for an enlarging soft tissue mass.

Exploring an Unfathomed Entiry: A Pooled Analysis of Solitory Skeletal Muscle Metastasis from Head and Neck Squamous Cell Carcinoma.

Background: Skeletal muscle is relatively uncommon site for metastasis in head and neck primary. This study was conducted to report our experience of three such cases and analyze the previously reported cases to assess the overall outcomes and formulate a treatment plan for these patients. Methods: We pooled the data extracted on extensive literature review and analyzed. Results: A total of 17 patients were analyzed for this study. All the patients had locally advanced primary and 14/17 developed metachronous metastasis. Median duration to development of metastasis was 8.5 months, and 13/17 patients had skeletal muscle as the only site of metastasis. Only 6/13 were treated with aggressive intent, 4 of which who underwent surgical resection had the best survival outcomes. Conclusions: Isolated skeletal muscle metastasis in a head and neck primary is relatively rare, and in future, the research work needs to be taken up afresh, on prospective model, with adequate patient sample, to draw a scientifically valid conclusion.

Skeletal Muscle Metastasis From Renal Cell Carcinoma: A Case Series and Literature Review.

Objectives: Skeletal muscle metastasis (SMM) from renal cell carcinoma (RCC) has been rarely reported. This case series was performed to increase the clinicians' understanding of its clinical features and treatments. Methods: We evaluated the clinical presentations, diagnoses, and treatments of 2 patients with SMM from RCC in our hospital and 39 cases reported in the literature. Results: Among the 41 patients, 4 (9.76%) were women and 37 (90.24%) were all men. The average age was 60.5 ± 12.6 years old (range from 7 to 81). The size of tumors varied from 1 to 28 cm, and the metastatic sites of 6 (14.63%) cases were in the heads, 20 (48.78%) in the limbs, 9 (21.95%) in the trunks, 3 (7.32%) in the buttock, and the other 3 (7.32%) were multiple sites. The mean of intervals between the RCC and the discovery of the first SMM was 73.61 months. More than half of the patients (25, 60.98%) were diagnosed by MRI and 25 (60.98%) patients performed a biopsy of the mass to establish the diagnosis. Finally, 30 (73.17%) cases performed mass excision. Then the adjuvant therapy was performed in 18 patients including immunotherapy, radiotherapy, chemotherapy, and targeted therapy. The median follow-up after SMM was 9 months (P25, P75: 5, 23), in which the longest survival time of patients with SMM of RCC was 8 years while the shortest was only 3 months. Conclusion: The characteristic clinical feature of SMM from RCC is asymptomatic masses or swelling with a long history which can be preoperative suspiciously diagnosed by MRI. The rapid biopsy of suspected lesions, determination of other metastasis sites, resection of metastasis, and systematic treatment are the recommended treatments of it.

Skeletal muscle metastases in neuroblastoma share common progenitors with primary tumor and biologically resemble stage MS disease.

Introduction: While subcutaneous metastases are often observed with stage MS neuroblastoma, an entity that usually resolves spontaneously, skeletal muscle metastases (SMM) have been rarely described. The purpose of this retrospective study was to investigate the significance of SMM in neuroblastoma. Patients and methods: Seventeen patients with neuroblastoma SMM were diagnosed at a median age of 4.3 (0.1-15.6) months. All had SMM at diagnosis and metastases at other sites. Fifteen (88%) had ≥ 2 SMM in disparate muscle groups. One, 14, and 2 patients had low, intermediate, and high-risk disease respectively. Fifteen tumors had favorable histology without MYCN amplification, and 2 were MYCN-amplified. Most SMM (80%; n=12/15 evaluated) were MIBG-avid. Results: Only 1 patient (with MYCN-non-amplified neuroblastoma) had disease progression. All survive at median follow-up of 47.9 (16.9-318.9) months post-diagnosis. Biological markers (histology, chromosomal and genetic aberrations) were not prognostic. Whole genome sequencing of 3 matched primary and SMM lesions suggested that both primary and metastatic tumors arose from the same progenitor. SMM completely resolved in 10 patients by 12 months post-diagnosis. Of 4 patients managed with watchful observation alone without any cytotoxic therapy, 3 maintain complete remission with SMM resolving by 5, 13, and 21 months post-diagnosis respectively. Conclusions: Children with neuroblastoma SMM have an excellent prognosis, with a clinical course suggestive of stage MS disease. Based on these results, the initial management of infants with non-MYCN-amplified NB with SMM could be watchful observation, which could eliminate or reduce exposure to genotoxic therapy.

Skeletal muscle metastasis with bone metaplasia from colon cancer: A case report and review of the literature.

BACKGROUND: Colon cancer is a common malignant disease of the gastrointestinal tract and usually occurs at the junction of the rectum and sigmoid colon. Lymphatic and hematogenous metastases occur frequently in colon cancer and the most common metastatic sites include the liver, lung, peritoneum, bone, and lymph nodes. As a manifestation of advanced tumor spread and metastasis, soft tissue metastasis, especially skeletal muscle metastasis with bone metaplasia caused by colon cancer, is rare, accounting for less than 1% of metastases. CASE SUMMARY: A 43-year-old male patient developed skeletal muscle metastasis with bone metaplasia of the right proximal thigh 5 mo after colon cancer was diagnosed. The patient was admitted to the hospital because of pain caused by a local mass on his right thigh. Positron emission tomography-computed tomography showed many enlarged lymph nodes around the abdominal aorta but no signs of lung or liver metastases. Color ultrasound revealed a mass located in the skeletal muscle and the results of histological biopsy revealed a poorly differentiated adenocarcinoma suspected to be distant metastases from colon cancer. Immunohistochemistry showed small woven bone components that were considered to be ossified. CONCLUSION: This case reminds us that for patients with advanced colorectal tumors, we should be alert to the possibility of unconventional metastasis.

Challenge of treating skeletal muscle metastasis during the COVID-19 pandemic in a low-resource setting.

BACKGROUND: The authors report on an extremely rare case of skeletal muscle metastasis from primary lung cancer that involved the radial nerve and humerus, which was 'over-treated' with wide tumour resection and frozen autograft reconstruction upon misdiagnosis of sarcoma by intraoperative frozen section, amid pressure of expediting hospital care in a low-resource setting during the coronavirus disease (COVID-19) pandemic. CASE PRESENTATION: A 61-year-old male living outside Metro Manila presented with painful mass in his left distal arm during the enhanced community quarantine, and requested admission upon testing negative for COVID-19. Imaging studies suggested a diagnosis of soft tissue sarcoma involving the radial nerve and humerus, and intending to prevent nosocomial severe acute respiratory syndrome coronavirus 2infection of patient, treatment was expedited by foregoing biopsy and opting for intraoperative frozen section prior to resection. Frozen section findings suggested malignancy intraoperatively, and surgical team proceeded with wide tumour resection and frozen autograft reconstruction of the humerus using plates and screws. However, permanent sections revealed metastatic carcinoma from primary non-small cell lung cancer, with positron emission tomography (PET) scan confirming lung mass in the right apical lobe. CONCLUSION: The report concludes that establishment of a definite tumour diagnosis by final histopathological analysis is indispensable, even when planning for emergent surgery in the time of the COVID-19 pandemic.

Malignant Phyllodes Breast Tumor: A Rare Case of Metastasis in Skeletal Muscle Detected on 18-Fluorodeoxyglucose Positron Emission Tomography.

Rapidly growing cystosarcoma phyllodes tumor (PT) of the breast are rarely encountered. Distant metastases are not uncommon in malignant PTs; however, rare sites of metastases are sometimes observed. Here, we present the case of a rapidly metastasizing malignant PT in which skeletal muscle metastasis was identified on 18F-fluorodeoxyglucose-based positron emission tomography-computed tomography reflecting its aggressive course and poor prognosis.

Carcinoma Lung Presenting with Skeletal Muscle Metastasis: Case Report with Review of Literature.

Lung cancers usually present very late with distant metastasis, thereby carrying a poor prognosis. Metastasis at unusual sites such as extremity musculature does create a diagnostic challenge. This leads to delay in diagnosis and treatment initiation and further worsens the prognosis of the patient. Not many cases have been reported as of now and no standard guidelines are available regarding clinical approach in such cases. We have presented one of such cases to emphasize on importance of early detection and differentiation of such lesions from primary soft tissue malignancies.

Skeletal muscle metastases of hepatocellular carcinoma: A case report and literature review.

BACKGROUND: The metastasis of liver cancer to skeletal muscle is extremely rare compared to other sites. We herein report a case of rapidly developing skeletal metastases following liver transplantation due to primary liver cancer. CASE SUMMARY: A 70-year-old male with underlying chronic hepatitis B virus infection was diagnosed with hepatocellular carcinoma (HCC), for which he underwent liver transplantation in 2014. Six years after receiving the transplant, pathological examination confirmed the presence of HCC without vascular invasion. He was admitted to the hospital with a rapidly growing mass on his right thigh. Ultrasound examination revealed a mixed echo mass in the lateral soft tissue of the middle part of the right femur. Magnetic resonance imaging showed heterogeneous iso-signal intensity on T1-weighted images and heterogeneous hyper-intensity on T2-weighted images compared to the surrounding muscles. Pathological examination of the ultrasound-guided needle biopsy specimen revealed that it was similar to the previously detected liver cancer; the diagnosis was metastasis of HCC. Surgical excision was performed. There were no other sites of metastasis, and the patient recovered well after surgery. CONCLUSION: This report presents a rare case of skeletal metastasis following liver transplantation for HCC. The study suggests a possible role for skeletal muscle metastasis mechanisms, which should be the focus of future research.