Lessons in clinical reasoning - pitfalls, myths, and pearls: shoulder pain as the first and only manifestation of lung cancer.

OBJECTIVES: Lung cancer is the leading cause of cancer-related death and poses significant challenges in diagnosis and management. Although muscle metastases are exceedingly rare and typically not the initial clinical manifestation of neoplastic processes, their recognition is crucial for optimal patient care. CASE PRESENTATION: We present a case report in which we identify the unique scenario of a 60-year-old man with shoulder pain and a deltoid muscle mass, initially suggestive of an undifferentiated pleomorphic sarcoma. However, further investigations, including radiological findings and muscle biopsy, revealed an unexpected primary lung adenocarcinoma. We performed a systematic literature search to identify the incidence of SMM and reflect on how to improve and build on better diagnosis for entities as atypical as this. This atypical presentation highlights the importance of recognizing and addressing cognitive biases in clinical decision-making, as acknowledging the possibility of uncommon presentations is vital. By embracing a comprehensive approach that combines imaging studies with histopathological confirmation, healthcare providers can ensure accurate prognoses and appropriate management strategies, ultimately improving patient outcomes. CONCLUSIONS: This case serves as a reminder of the need to remain vigilant, open-minded, and aware of cognitive biases when confronted with uncommon clinical presentations, emphasizing the significance of early recognition and prompt evaluation in achieving optimal patient care.

Reversed shoulder arthroplasty leads to significant histological changes of the deltoid muscle: a prospective intervention trial.

INTRODUCTION: Reverse shoulder arthroplasty (RSA) shows promising short- and mid-term results in cuff tear arthropathy. However, functional impairments are described in long-term findings. Micromorphological changes in the periarticular musculature could be in part responsible for this, but have not yet been analysed. Thus, histological changes of the deltoid muscle and their association to the functional outcome were evaluated in this study. MATERIAL AND METHODS: A total of 15 patients treated with RSA were included in this prospective study. Functional outcome was assessed using the Constant Score (CS) and the DASH (disabilities of the arm, shoulder and hand) Score before RSA and after a mean follow-up of 12 months. Deltoid muscle biopsies were harvested intraoperatively and 12 months postoperatively. Mean deltoid muscle fibre area (MMFA) was calculated histologically after haematoxylin-eosin staining. RESULTS: Postoperative shoulder function significantly improved within 12 months (CS: Δ 37.4 ± 22.6, p = 0.001; DASH: Δ 27.1 ± 29.1, p = 0.006). The MMFA significantly decreased (p = 0.02), comparing the results from the intraoperative biopsy (MMFA: 8435.8 µm2, SD ± 5995.9 µm2) to the 12 months biopsy (MMFA: 5792. µm2, SD ± 3223.6 µm2). No correlation could be found between the functional score results and MMFA. CONCLUSION: Signs of deltoid muscle changes in terms of a reduced MMFA can be detected 1 year after RSA and thus already a long time before long-term functional impairments become apparent. Further studies with larger patient series and longer follow-up periods as well as extended histological assessments and simultaneous radiological examinations are required.

Fourier-Transform Infrared Spectroscopy of Skeletal Muscle Tissue: Expanding Biomarkers in Primary Mitochondrial Myopathies.

Primary mitochondrial myopathies (PMM) are a group of mitochondrial disorders characterized by a predominant skeletal muscle involvement. The aim of this study was to evaluate whether the biochemical profile determined by Fourier-transform infrared (FTIR) spectroscopic technique would allow to distinguish among patients affected by progressive external ophthalmoplegia (PEO), the most common PMM presentation, oculopharyngeal muscular dystrophy (OPMD), and healthy controls. Thirty-four participants were enrolled in the study. FTIR spectroscopy was found to be a sensitive and specific diagnostic marker for PEO. In particular, FTIR spectroscopy was able to distinguish PEO patients from those affected by OPMD, even in the presence of histological findings similar to mitochondrial myopathy. At the same time, FTIR spectroscopy differentiated single mtDNA deletion and mutations in POLG, the most common nuclear gene associated with mitochondrial diseases, with high sensitivity and specificity. In conclusion, our data suggest that FTIR spectroscopy is a valuable biodiagnostic tool for the differential diagnosis of PEO with a high ability to also distinguish between single mtDNA deletion and mutations in POLG gene based on specific metabolic transitions.

Rare Epstein-Barr Virus-Associated Smooth Muscle Tumor in a Patient with AIDS: A Case Report.

CASE: A 34-year-old man with poorly controlled acquired immune deficiency syndrome underwent excision of a left arm mass. The histopathologic workup identified the features of an Epstein-Barr virus-associated smooth muscle tumor (EBV-SMT). The patient was readmitted 5 months later for vomiting and found to have liver metastases that were confirmed to be EBV-SMT. Six months after discharge, there was no recurrence of the arm mass or increase in the size of the liver metastases. CONCLUSION: Most commonly found in immunocompromised patients, EBV-SMTs are rare tumors that can be mistaken for a leiomyosarcoma.

Functional evaluation following deltoid muscle resection in patients with soft tissue sarcoma.

BACKGROUND: The present study aimed to determine functional outcomes in patients undergoing deltoid muscle resection for soft tissue sarcoma. METHODS: Between 2002 and 2014, 18 patients with soft tissue sarcoma of the shoulder who underwent wide resection including the deltoid muscle, and were followed up for more than 12 months, were retrospectively included in the study. In all, 11 patients were male and 7 were female. The median age was 59 years, median follow-up duration was 37 months. The extent of resection of deltoid muscle, with or without rotator cuff damage, reconstruction methods, adjuvant therapy, oncological outcomes, and the International Society of Limb Salvage (ISOLS) score as functional outcomes were analyzed. RESULTS: Six patients underwent total resection, and twelve underwent partial resections of deltoid muscle. The rotator cuff was resected in four patients. Soft tissue reconstruction was performed in 17 patients using a pedicled latissimus dorsi muscle flap. Two local recurrences and three distant metastases occurred during follow-up. Median overall survival was 72 months. The mean ISOLS score was 25.0 points (±4.6points). Univariate analysis revealed that there was no significant difference in ISOLS score regarding the extent of deltoid muscle resection. Multivariate analysis identified only combined resection of the rotator cuff as a significant prognostic factor for poor functional outcomes (P < 0.001). CONCLUSIONS: The extent of resection of the deltoid muscle might not affect the functional outcomes determined by ISOLS score. If the rotator cuff is resected concurrently, satisfactory functional outcomes might not be obtained.

X-linked Emery-Dreifuss muscular dystrophy manifesting with adult onset axial weakness, camptocormia, and minimal joint contractures.

Emery-Dreifuss muscular dystrophy is an early-onset, slowly progressive myopathy characterized by the development of multiple contractures, muscle weakness and cardiac dysfunction. We present here the case of a 65-year-old male patient with a 20 year history of slowly progressive camptocormia, bradycardia and shortness of breath. Examination showed severe spine extensor and neck flexor muscle weakness with slight upper limb proximal weakness. Cardiologic assessment revealed slow atrial fibrillation. Whole body MRI demonstrated adipose substitution of the paravertebral, limb girdle and peroneal muscles as well as the tongue. Emerin immunohistochemistry on patient muscle biopsy revealed the absence of nuclear envelope labeling confirmed by Western Blot. Genetic analysis showed a hemizygous duplication of 5 bases in exon 6 of the EMD, emerin, gene on the X chromosome. This is an unusual presentation of X-linked Emery-Dreifuss muscular dystrophy with adult onset, predominant axial muscles involvement and minimal joint contractures. Diagnosis was prompted by the analysis of emerin on muscle biopsy.

Calcified leiomyoma of the deltoid: pathophysiology and imaging review.

Leiomyomas are benign tumors of smooth muscle cells. Leiomyomas of somatic soft tissue are a specific class of leiomyoma believed to arise from the smooth muscle cells found in the walls of blood vessels and represent less than 4% of benign, somatic soft tissue tumors. Of the somatic soft tissue tumors, approximately one-third will become calcified. We report an intramuscular, calcified leiomyoma arising from the left deltoid of a 47-year-old Caucasian male. To the best of the authors' knowledge, this is the first reported case of a calcified, intramuscular leiomyoma of the deltoid. Imaging studies and patient presentation were initially suggestive of tumoral calcinosis or myositis ossificans. It was not until pathologic examination that the correct diagnosis of the calcified leiomyoma was made. Leiomyoma should be included in the differential diagnosis of calcified soft tissue masses. If excised with adequate margins, recurrence is unlikely.

Elevated IL-4 and IFN-γ Levels in Muscle Tissue of Patients with Dermatomyositis.

BACKGROUND/AIM: To investigate the contribution of muscle tissue-derived cytokines in dermatomyositis (DM). MATERIALS AND METHODS: Muscle homogenates were prepared from deltoid muscle biopsy specimens of 10 patients with DM and eight controls with no pathological signs of myopathy. Interleukin (IL)-4, interferon (IFN)-γ and IL-17 levels were evaluated by enzyme-linked immunosorbent assay (ELISA) and immunoblotting analysis. Muscle strength grades were recorded. RESULTS: Patients with DM showed significantly elevated muscle tissue IL-4 and IFN-γ levels, whereas IL-17 levels were comparable between patients with DM and controls. Immunoblotting studies confirmed ELISA results. In DM muscle specimens, IL-4 and IFN-γ levels were positively correlated, while no correlation was observed between IL-17 and the other two cytokines. Moreover, IL-4 and IFN-γ levels were significantly negative correlated with muscle strength grades for the deltoid muscle. CONCLUSION: Our results confirm the involvement of T helper (Th) 1-type and Th2-type immunity in DM pathogenesis. Muscle tissue appears to contribute to muscle weakness in DM by producing inflammatory cytokines.

Deltoid muscle volume affects clinical outcome of reverse total shoulder arthroplasty in patients with cuff tear arthropathy or irreparable cuff tears.

We aimed to estimate the interrelation between preoperative deltoid muscle status by measuring the 3-dimensional deltoid muscle volume and postoperative functional outcomes after reverse total shoulder arthroplasty(RTSA). Thirty-five patients who underwent RTSA participated in this study. All patients underwent preoperative magnetic resonance imaging(MRI) as well as pre- and postoperative radiography and various functional outcome evaluations at least 1 year. The primary outcome parameter was set as age- and sex-matched Constant scores. The 3-dimensional deltoid muscle model was generated using a medical image processing software and in-house code, and the deltoid muscle volume was calculated automatically. Various clinical and radiographic factors comprising the deltoid muscle volume adjusted for body mass index(BMI) were analyzed, and their interrelation with the outcome parameters was appraised using a multivariate analysis. As a result, all practical consequences considerably improved following surgery(all p<0.01). Overall, 20 and 15 indicated a higher and a lower practical consequence than the average, respectively, which was assessed by the matched Constant scores. The deltoid muscle volume adjusted for BMI(p = 0.009), absence of a subscapularis complete tear (p = 0.040), and greater change in acromion-deltoid tuberosity distance(p = 0.013) were associated with higher matched Constant scores. Multivariate analysis indicated that the deltoid muscle volume was the single independent prognostic factor for practical consequences(p = 0.011). In conclusion, the preoperative deltoid muscle volume significantly affected the functional outcome following RTSA in patients with cuff tear arthropathy or irreparable cuff tears. Therefore, more attention should be paid to patients with severe atrophied deltoid muscle who are at a high risk for poor practical consequences subsequent to RTSA.

Complete deltoid resection in early childhood without muscle transfer results in normal shoulder function at long-term follow-up: a case report.

BACKGROUND: Musculoskeletal tumors involving the deltoid muscle and necessitating its complete resection are rare. The function after complete deltoid resection is reported to be limited, and several authors consider muscle transfer to improve shoulder motion. However, it still remains unclear whether such transfer adds function. To the best of our knowledge, all reports on complete deltoid resection refer to adult patients, and it is unknown what function results after deltoid resection in childhood. The remaining muscles may have the potential to compensate for the loss of deltoid function. CASE PRESENTATION: Here we report the case of a 5-year-old white boy with complete (isolated) deltoid muscle resection in infancy for a large aggressive soft tissue tumor. No reconstructive procedure or muscle transfer was performed at the time of index surgery. Pathology revealed an angiomatoid fibrous histiocytoma. His postoperative course was uneventful. At 11 years of follow-up, he remained disease-free and had excellent shoulder function, including normal range of motion. CONCLUSIONS: This report implies that major muscles such as the deltoid can be resected in a child without compromising long-term function. Therefore, a muscle transfer at index surgery is probably not necessary.

Murine supraspinatus tendon injury model to identify the cellular origins of rotator cuff healing.

Purpose of this study: To elucidate the origin of cell populations that contribute to rotator cuff healing, we developed a mouse surgical model where a full-thickness, central detachment is created in the supraspinatus. MATERIALS AND METHODS: Three different inducible Cre transgenic mice with Ai9-tdTomato reporter expression (PRG4-9, αSMA-9, and AGC-9) were used to label different cell populations in the shoulder. The defect was created surgically in the supraspinatus. The mice were injected with tamoxifen at surgery to label the cells and sacrificed at 1, 2, and 5 weeks postoperatively. Frozen sections were fluorescently imaged then stained with Toluidine Blue and re-imaged. RESULTS: Three notable changes were apparent postoperatively. (1) A long thin layer of tissue formed on the bursal side overlying the supraspinatus tendon. (2) The tendon proximal to the defect initially became hypercellular and disorganized. (3) The distal stump at the insertion underwent minimal remodeling. In the uninjured shoulder, tdTomato expression was seen in the tendon midsubstance and paratenon cell on the bursal side in PRG4-9, in paratenon, blood vessels, and periosteum of acromion in SMA-9, and in articular cartilage, unmineralized fibrocartilage of supraspinatus enthesis, and acromioclavicular joint in AGC-9 mice. In the injured PRG4-9 and SMA-9 mice, the healing tissues contained an abundant number of tdTomato+ cells, while minimal contribution of tdTomato+ cells was seen in AGC-9 mice. CONCLUSIONS: The study supports the importance of the bursal side of the tendon to rotator cuff healing and PRG4 and αSMA may be markers for these progenitor cells.

Glomus tumor located in deltoid muscle.

Glomus tumors are benign soft tissue neoplasms arising from the glomus body, which are primarily found under the nail bed of the fingers. They are rarely located in other parts of the body. Only 8 cases of glomus tumors around the shoulder have been published in the literature. The purpose of this study was to present a glomus tumor located in the deltoid muscle in a 68-year-old male patient that was surgically treated by marginal excision. The patient remained asymptomatic, and no recurrence was detected at 2-year follow up.

Is deltoid muscle biopsy useful in isolated camptocormia? A prospective study.

BACKGROUND AND PURPOSE: Camptocormia is a marked anterior curvature of the thoracolumbar spine that may be caused by parkinsonism, amyotrophic lateral sclerosis (ALS), myasthenia gravis (MG) and muscle disease. The interest of a systematic muscle biopsy has not been evaluated until now. In our study, the aim was to prospectively evaluate the proportion of patients with isolated camptocormia without ALS, MG and parkinsonism who have an underlying myopathy. METHODS: Twenty consecutive patients (75% female, mean age 70 years) with isolated camptocormia were enrolled in a single centre in this 5-year prospective study. ALS, MG and parkinsonism had been excluded in all cases. A left deltoid muscle biopsy was performed in all patients and processed with standard techniques for histology and immunohistochemistry. Additional biochemical and genetic studies were performed when pathological analysis was consistent with myopathy. RESULTS: A myopathy was identified in seven patients (35%). Three patients presented with mitochondrial myopathy, including two patients harbouring a heterozygous POLG gene pathogenic variant and one patient with a heterozygous RRM2B gene pathogenic variant. Two patients presented with an inflammatory myopathy, including one with anti-PM/Scl antibodies. One patient presented with facioscapulohumeral muscular dystrophy and one patient with an MYH7 gene-related myofibrillar myopathy. No obvious myopathy was found in the 13 remaining cases. DISCUSSION: In this prospective study, an underlying myopathy was found in 35% of patients with isolated camptocormia. These results suggest that a muscle biopsy should be systematically performed in patients with isolated camptocormia when ALS, MG and parkinsonism have been excluded.

Alterations of the Deltoid Muscle After Open Versus Arthroscopic Rotator Cuff Repair.

BACKGROUND: Open repair can be more useful than arthroscopic repair for immobile and severely retracted, large to massive rotator cuff tears. However, it is not known whether the deltoid muscle is altered after open repair or to what extent the deltoid origin remains detached after surgery. PURPOSE: To compare postoperative alterations of the deltoid muscle in open versus arthroscopic repair for severely retracted, large to massive rotator cuff tears. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Enrolled in this study were 135 patients who underwent surgical repair for severely retracted, large to massive rotator cuff tears and who had routine follow-up MRIs at least 6 months after surgery. Open repairs were performed in 56 cases and arthroscopic repairs in 79 cases. The detachment and thickness of the deltoid muscle at its proximal origin were recorded in 5 zones on MRI. The alterations of the deltoid muscle and postoperative integrity of the repaired rotator cuff were evaluated. RESULTS: Partial detachment of the deltoid occurred in 1 patient (1.8%) in the open group and in 2 patients (2.5%) in the arthroscopic group (P = .80). All the partial detachments occurred in zones 2 and 3. Attenuation of the proximal origin of the deltoid was found in 3 patients (5.4%) in the open group and in 4 patients (5.1%) in the arthroscopic group (P = .87). Atrophy of the deltoid muscle was shown in 3 patients (5.4%) in the open group and 4 patients (5.1%) in the arthroscopic group (P = .61). The retear rate of the repaired cuff was 30.4% (17/56) in the open group and 38.0% (30/79) in the arthroscopic group (P = .74). CONCLUSION: Between open and arthroscopic repair for severely retracted, large to massive rotator cuff tears, there was no significant difference in detachment of the deltoid origin and alterations of the deltoid muscle after repair. Postoperative alterations of the deltoid occurred in arthroscopic surgery as well as in open surgery. For immobile massive rotator cuff tear, open repair is an acceptable technique as long as the deltoid muscle is meticulously reattached after surgery.