Guidelines for Pathologic Diagnosis of Mesothelioma.

CONTEXT.­: Mesothelioma is an uncommon tumor that can be difficult to diagnose. OBJECTIVE.­: To provide updated, practical guidelines for the pathologic diagnosis of mesothelioma. DATA SOURCES.­: Pathologists involved in the International Mesothelioma Interest Group and others with expertise in mesothelioma contributed to this update. Reference material includes peer-reviewed publications and textbooks. CONCLUSIONS.­: There was consensus opinion regarding guidelines for (1) histomorphologic diagnosis of mesothelial tumors, including distinction of epithelioid, biphasic, and sarcomatoid mesothelioma; recognition of morphologic variants and patterns; and recognition of common morphologic pitfalls; (2) molecular pathogenesis of mesothelioma; (3) application of immunohistochemical markers to establish mesothelial lineage and distinguish mesothelioma from common morphologic differentials; (4) application of ancillary studies to distinguish benign from malignant mesothelial proliferations, including BAP1 and MTAP immunostains; novel immunomarkers such as Merlin and p53; fluorescence in situ hybridization (FISH) for homozygous deletion of CDKN2A; and novel molecular assays; (5) practical recommendations for routine reporting of mesothelioma, including grading epithelioid mesothelioma and other prognostic parameters; (6) diagnosis of mesothelioma in situ; (7) cytologic diagnosis of mesothelioma, including use of immunostains and molecular assays; and (8) features of nonmalignant peritoneal mesothelial lesions.

Utility of LEF1 to differentiate desmoid fibromatosis from its histologic mimics.

Diagnosis of desmoid-type fibromatosis (DF) may be challenging on biopsy due to morphologic overlap with reactive fibrosis (scar) and other uniform spindle cell neoplasms. Evaluation of nuclear ß-catenin, a surrogate of Wnt pathway activation, is often difficult in DF due to weak nuclear expression and high background membranous/cytoplasmic staining. Lymphoid enhancer-factor 1 (LEF1) is a recently characterized effector partner of ß-catenin which activates the transcription of target genes. We investigated the performance of LEF1 and ß-catenin immunohistochemistry in a retrospective series of 156 soft tissue tumors, including 35 DF, 3 superficial fibromatosis, and 121 histologic mimics (19 soft tissue perineurioma, 8 colorectal perineurioma, 4 intraneural perineurioma, 26 scars, 23 nodular fasciitis, 6 low-grade fibromyxoid sarcomas, 6 angioleiomyomas, 5 neurofibromas, 5 dermatofibrosarcoma protuberans, 3 low-grade myofibroblastic sarcomas, 3 synovial sarcomas, 3 inflammatory myofibroblastic tumors, 2 schwannomas, and 1 each of Gardner-associated fibroma, radiation-associated spindle cell sarcoma, sclerotic fibroma, dermatofibroma, and glomus tumor). LEF1 expression was not only seen in 33/35 (94%) of DF but also observed in 19/23 (82%) nodular fasciitis, 7/19 (37%) soft tissue perineurioma, 2/3 (66%) synovial sarcoma, and 6/26 (23%) scar, as well as in 1 radiation-associated spindle cell sarcoma. The sensitivity and specificity of LEF1 IHC for diagnosis of DF were 94% and 70%, respectively. By comparison, ß-catenin offered similar sensitivity, 94%, but 88% specificity. Positivity for LEF1 and ß-catenin in combination showed sensitivity of 89%, lower than the sensitivity of ß-catenin alone (94%); however, the combination of both LEF1 and ß-catenin improved specificity (96%) compared to the specificity of ß-catenin alone (88%). Although LEF1 has imperfect specificity in isolation, this stain has diagnostic utility when used in combination with ß-catenin.

Single-Cell Sequencing Illuminates Thymic Development: An Updated Framework for Understanding Thymic Epithelial Tumors.

Thymic epithelial tumors (TETs) are rare tumors for which treatment options are limited. The ongoing need for improved systemic therapies reflects a limited understanding of tumor biology as well as the normal thymus. The essential role of the thymus in adaptive immunity is largely effected by its epithelial compartment, which directs thymocyte (T-cell) differentiation and immunologic self-tolerance. With aging, the thymus undergoes involution whereby epithelial tissue is replaced by adipose and other connective tissue, decreasing immature T-cell production. Against this natural drive toward involution, a fraction of thymuses will instead undergo oncologic transformation, leading to the formation of TETs, including thymoma and thymic carcinoma. The rarity of these tumors restricts investigation of the mechanisms of tumorigenesis and development of rational treatment options. To this end, the development of technologies which allow deep molecular profiling of individual tumor cells permits a new window through which to view normal thymic development and contrast the malignant changes that result in oncogenic transformation. In this review, we describe the findings of recent illuminating studies on the diversity of cell types within the epithelial compartment through thymic differentiation and aging. We contextualize these findings around important unanswered questions regarding the spectrum of known somatic tumor alterations, cell of origin, and tumor heterogeneity. The perspectives informed by single-cell molecular profiling offer new approaches to clinical and basic investigation of thymic epithelial tumors, with the potential to accelerate development of improved therapeutic strategies to address ongoing unmet needs in these rare tumors.

Phosphaturic mesenchymal tumor: management and outcomes of ten patients treated at a single institution.

BACKGROUND: Phosphaturic mesenchymal tumor (PMT) is a rare tumor that causes tumor-induced osteomalacia. Patients present with non-specific symptoms secondary to renal phosphate wasting and decreased bone mineralization. We sought to assess: (1) What are the common presenting features, laboratory and imaging findings, histologic findings of phosphaturic mesenchymal tumors? (2) What are the available treatment strategies for phosphaturic mesenchymal tumors and their long-term outcomes in terms of local recurrence and symptom control after treatment? METHODS: We retrospectively identified patients with a histologic diagnosis of PMT located in the axial or appendicular skeleton, or surrounding soft tissues. A total of 10 patients were finally included in our study. RESULTS: Median tumor size was 1.9 cm (range, 1.1 to 6.1) and median time from symptom onset to diagnosis was 3 years (range, 0.5 to 15 years). All patients but one presented with hypophosphatemia (median 1.9 mg/dL, range 1.2 to 3.2). Pre-operative FGF-23 was elevated in all cases (median 423.5 RU/mL, range 235 to 8950). Six patients underwent surgical resection, three were treated percutaneously (radiofrequency ablation or cryoablation), and one refused treatment. Only one patient developed local recurrence and no patients developed metastatic disease. At last follow-up, nine patients showed no evidence of disease and one was alive with disease. CONCLUSION: Phosphaturic mesenchymal tumor is a rare tumor presenting with non-specific symptoms. Surgery is the standard treatment when negative margins can be achieved without significant morbidity. In patients with small tumors in surgically-inaccessible areas, radiofrequency ablation or cryoablation can be performed successfully.

Acquired Cross-resistance in Small Cell Lung Cancer due to Extrachromosomal DNA Amplification of MYC paralogs.

Small cell lung cancer (SCLC) presents as a highly chemosensitive malignancy but acquires cross-resistance after relapse. This transformation is nearly inevitable in patients but has been difficult to capture in laboratory models. Here, we present a pre-clinical system that recapitulates acquired cross-resistance, developed from 51 patient-derived xenograft (PDX) models. Each model was tested in vivo against three clinical regimens: cisplatin plus etoposide, olaparib plus temozolomide, and topotecan. These drug-response profiles captured hallmark clinical features of SCLC, such as the emergence of treatment-refractory disease after early relapse. For one patient, serial PDX models revealed that cross-resistance was acquired through MYC amplification on extrachromosomal DNA (ecDNA). Genomic and transcriptional profiles of the full PDX panel revealed that MYC paralog amplifications on ecDNAs were recurrent in relapsed cross-resistant SCLC, and this was corroborated in tumor biopsies from relapsed patients. We conclude that ecDNAs with MYC paralogs are recurrent drivers of cross-resistance in SCLC.

Molecular and Immunohistochemical Testing in Mesothelioma and Other Mesothelial Lesions.

CONTEXT.­: Molecular testing has increasingly been utilized in the evaluation of mesothelioma. Diffuse mesothelioma comprises multiple distinct genetic subgroups. While most diffuse mesotheliomas lack oncogenic kinase mutations and instead harbor alterations involving tumor suppressors and chromatin regulators, a minor subset of tumors is characterized by uncommon alterations such as germline mutations, genomic near-haploidization, ALK rearrangement, ATF1 rearrangement, or EWSR1::YY1 fusion. OBJECTIVE.­: To provide updates on the salient molecular features of diffuse mesothelioma, mesothelioma in situ, and other mesothelial lesions: well-differentiated papillary mesothelial tumor, adenomatoid tumor, peritoneal inclusion cyst, and others. We consider the diagnostic, prognostic, and predictive utility of molecular testing in mesothelial lesions. DATA SOURCES.­: We performed a literature review of recently described genetic features, molecular approaches, and immunohistochemical tools, including BAP1, MTAP, and merlin in mesothelioma and other mesothelial lesions. CONCLUSIONS.­: Our evolving understanding of the molecular diversity of diffuse mesothelioma and other mesothelial lesions has led to considerable changes in pathology diagnostic practice, including the application of immunohistochemical markers such as BAP1, MTAP, and merlin (NF2), which are surrogates of mutation status. In young patients and/or those without significant asbestos exposure, unusual mesothelioma genetics such as germline mutations, ALK rearrangement, and ATF1 rearrangement should be considered.

Does Wound VAC Temporization Offer Patient-Reported Outcomes Similar to Single-Stage Excision Reconstruction After Myxofibrosarcoma Resection?

BACKGROUND: Vacuum-assisted closure (VAC) temporization is a promising technique to achieve local control in aggressive soft tissue sarcomas. Despite its previously reported efficacy, adoption of VAC temporization remains limited, primarily due to the scarce literature on patient-reported outcomes (PROs) supporting its efficacy. This study compared the postoperative PROs after VAC temporization or single-stage (SS) excision and reconstruction for patients undergoing surgical resection for myxofibrosarcoma management. METHODS: A retrospective analysis of myxofibrosarcoma patients who underwent surgical resections at our institution from 2016 to 2022 was performed. Postoperative PROs collected prospectively for those treated with VAC temporization or SS excision/reconstruction were compared using a visual analog scale (VAS) for pain and three Patient-Reported Outcomes Measurement Information System (PROMIS) questionnaires: Global Health Short-Form Mental (SF Mental), Global Health Short-Form Physical (SF Physical), and Physical Function Short-Form 10a (SF 10a). Absolute and differential (postoperative minus preoperative) scores at the 1-month, 3-month, 6-month, 1-year, and 2-year time points were compared. RESULTS: The analysis included 79 patients (47 treated with VAC temporization and 32 treated with SS excision/reconstruction). All outcomes were similar between the groups except for physical function 1 year after surgery, in which the differential PROMIS SF 10a scores were higher in the SS group (p = 0.001). All the remaining absolute and differential PROMIS and VAS pain scores were similar between the groups at all time points. Postoperative complications did not differ between the groups. CONCLUSION: The PROs for physical and mental health, physical function, and pain were similar between the myxofibrosarcoma patients who had VAC temporization and those who had SS excision/reconstruction after surgical resection.

Anastomosing haemangioma of the mediastinum: Clinicopathological series with radiological and genetic characterisation.

AIMS: Anastomosing haemangiomas are benign tumours with anastomosing vascular channels that may mimic angiosarcoma. While anastomosing haemangiomas have been described in diverse locations, particularly the abdominal/paraspinal region, data on anastomosing haemangiomas in the mediastinum remain limited. We report the clinicopathological, radiological and molecular characteristics of the largest single-institutional series of mediastinal anastomosing haemangiomas. METHODS AND RESULTS: In our pathology archives in 2011-23, we reviewed all vascular lesions involving the mediastinum and identified seven anastomosing haemangiomas. Clinical information was abstracted from medical charts; available radiological imaging was reviewed. Targeted DNA-based next-generation sequencing (447 genes, including GNAQ and GNA11) was performed on five cases. The seven patients included five women and two men, with an age range of 55-77 (median = 72) years. Of the six tumours with available radiology, two each were in the prevascular, visceral and paravertebral mediastinum, with lobulated peripheral enhancement in all tumours examined with contrast enhancement. Six patients underwent tumour resection; one patient received proton radiotherapy. Microscopically, each tumour was solitary and characterised by anastomosing capillary-sized vessels lined by hobnail endothelial cells. Fibrin microthrombi, hyaline globules and extramedullary haematopoiesis were common. In the five tumours analysed by next-generation sequencing, GNAQ p.Q209P was identified in one tumour; no additional reportable alterations were identified in the remaining cases. No recurrence was noted in the four patients with available follow-up of 3-58 (median = 9.5) months after resection. CONCLUSION: While mediastinal anastomosing haemangiomas can microscopically mimic angiosarcoma, awareness of this entity and radiological correlation may help to circumvent this diagnostic pitfall.

Mesenchymal tumours of the pleura: review and update.

Primary mesenchymal tumours of the pleura are uncommon and can be diagnostically challenging due to their overlapping histopathologic and immunophenotypic features. Herein we discuss selected mesenchymal tumours of the pleura, including solitary fibrous tumour, calcifying fibrous tumour, desmoid fibromatosis, synovial sarcoma, schwannoma, malignant peripheral nerve sheath tumour, inflammatory myofibroblastic tumour, follicular dendritic cell sarcoma, epithelioid hemangioendothelioma, and desmoplastic small round cell tumour. We review their clinicopathologic characteristics, along with an update on the relevant immunohistochemical and molecular features.

Surgical Resection of Benign Nodules in Lung Cancer Screening: Incidence and Features.

Introduction: Interventions and surgical procedures are common for nonmalignant lung lesions detected on lung cancer screening (LCS). Inadvertent surgical resection of benign nodules with a clinical suspicion of lung cancer can occur, can be associated with complications, and adds to the cost of screening. The objective of this study is to assess the characteristics of surgically resected benign nodules detected on LCS computed tomography which were presumed to be lung cancers. Methods: This retrospective study included 4798 patients who underwent LCS between June 2014 and January 2021. The benign lung nodules, surgically resected with a presumed cancer diagnosis, were identified from the LCS registry. Patient demographics, imaging characteristics, and pathologic diagnoses of benign nodules were analyzed. Results: Of the 4798 patients who underwent LCS, 148 (3.1%) underwent surgical resection of a lung nodule, and of those who had a resection, 19 of 148 (12.8%) had a benign diagnosis (median age = 64 y, range: 56-77 y; F = 12 of 19, 63.2%; M = seven of 19, 36.8%). The median nodule size was 10 mm (range: 6-31 mm). Most nodules were solid (15 of 19, 78.9%), located in the upper lobes (11 of 19; 57.9%), and were peripheral (17 of 19, 89.5%). Most nodules (13 of 17; 76.5%) had interval growth, and four of 17 (23.5%) had increased fluorodeoxyglucose uptake. Of the 19 patients, 17 (89.5%) underwent sublobar resection (16 wedge resection and one segmentectomy), whereas two central nodules (10.5%) had lobectomies. Pathologies identified included focal areas of fibrosis or scarring (n = 8), necrotizing granulomatous inflammation (n = 3), other nonspecific inflammatory focus (n = 3), benign tumors (n = 3), reactive lymphoid hyperplasia (n = 1), and organizing pneumonia (n = 1). Conclusions: Surgical resections of benign nodules that were presumed malignant are infrequent and may be unavoidable given overlapping imaging features of benign and malignant nodules. Knowledge of benign pathologies that can mimic malignancy may help reduce the incidence of unnecessary surgeries.

Fluorescence lifetime of injected indocyanine green as a universal marker of solid tumours in patients.

The surgical resection of solid tumours can be enhanced by fluorescence-guided imaging. However, variable tumour uptake and incomplete clearance of fluorescent dyes reduces the accuracy of distinguishing tumour from normal tissue via conventional fluorescence intensity-based imaging. Here we show that, after systemic injection of the near-infrared dye indocyanine green in patients with various types of solid tumour, the fluorescence lifetime (FLT) of tumour tissue is longer than the FLT of non-cancerous tissue. This tumour-specific shift in FLT can be used to distinguish tumours from normal tissue with an accuracy of over 97% across tumour types, and can be visualized at the cellular level using microscopy and in larger specimens through wide-field imaging. Unlike fluorescence intensity, which depends on imaging-system parameters, tissue depth and the amount of dye taken up by tumours, FLT is a photophysical property that is largely independent of these factors. FLT imaging with indocyanine green may improve the accuracy of cancer surgeries.

High dose, dual-release polymeric films for extended surgical bed paclitaxel delivery.

While surgery represents a major therapy for most solid organ cancers, local recurrence is clinically problematic for cancers such as sarcoma for which adjuvant radiotherapy and systemic chemotherapy provide minimal local control or survival benefit and are dose-limited due to off-target side effects. We describe an implantable, biodegradable poly(1,2-glycerol carbonate) and poly(caprolactone) film with entrapped and covalently-bound paclitaxel enabling safe, controlled, and extended local delivery of paclitaxel achieving concentrations 10,000× tissue levels compared to systemic administration. Films containing entrapped and covalently-bound paclitaxel implanted in the tumor bed, immediately after resection of human cell line-derived chondrosarcoma and patient-derived xenograft liposarcoma and leiomyosarcoma in mice, improve median 90- or 200-day recurrence-free and overall survival compared to control mice. Furthermore, mice in the experimental film arm show no film-related morbidity. Continuous, extended, high-dose paclitaxel delivery via this unique polymer platform safely improves outcomes in three different sarcoma models and provides a rationale for future incorporation into human trials.

Concordance of ASCL1, NEUROD1 and POU2F3 transcription factor-based subtype assignment in paired tumour samples from small cell lung carcinoma.

AIMS: Small cell lung carcinoma (SCLC) can be classified into transcription factor-based subtypes (ASCL1, NeuroD1, POU2F3). While in-vitro studies suggest intratumoral heterogeneity in the expression of these markers, how SCLC subtypes vary over time and among locations in patients remains unclear. METHODS AND RESULTS: We searched a consecutive series of patients at our institution in 2006-22 for those with greater than one available formalin-fixed paraffin-embedded SCLC sample in multiple sites and/or time-points. Immunohistochemistry for ASCL1, NeuroD1 and POU2F3 was performed and evaluated using H-scores, with subtype assigned based on the positive marker (H-score threshold >10) with the highest H-score. The 179 samples (75, lung; 51, lymph nodes; 53, non-nodal metastases) from 84 patients (74 with two, 10 with more than two samples) included 98 (54.7%) ASCL1-dominant, 47 (26.3%) NeuroD1-dominant, 15 (8.4%) POU2F3-dominant, 17 (9.5%) triple-negative and two (1.1%) ASCL1/NeuroD1 co-dominant samples. NeuroD1-dominant subtype was enriched in non-lung locations. Subtype concordance from pairwise comparison was 71.4% overall and 89.7% after accounting for ASCL1/NeuroD1-dual expressors and technical factors including <500 cells/slide, H-score thresholds and sample decalcification. No significant difference in subtype concordance was noted with a longer time lapse or with extrathoracic versus intrathoracic samples in this cohort. CONCLUSIONS: After accounting for technical factors, transcription factor-based subtyping was discordant among multiple SCLC samples in ~10% of patients, regardless of sample locations and time lapse. Our findings highlighted the spatiotemporal heterogeneity of SCLC in clinical samples and potential challenges, including technical and biological factors, that might limit concordance in SCLC transcription factor-based subtyping.

Lobectomy for Suspected Lung Cancer Without Prior Diagnosis.

BACKGROUND: We describe use, patients, and outcome of diagnostic lobectomy for suspected lung cancer without pathologic confirmation. METHODS: A retrospective review of consecutive lobectomy or bilobectomy for suspected or confirmed primary pulmonary malignancy was conducted using our participant's sample of The Society of Thoracic Surgeons database. Surgeons performed lobectomy based on clinical diagnosis or confirmation on a biopsy specimen. Lung cancer confirmed by biopsy specimen was compared with cases clinically suspected. Univariate and multivariate analyses identified variables associated with lobectomy without biopsy specimen confirmation. RESULTS: Among 2651 lobectomies performed between 2006 and 2019 in 2617 patients, lung cancer was confirmed by preoperative biopsy specimen in 51.6% (1368 of 2651) or was clinically suspected before the operation in 48.4% (1283 of 2651). The intraoperative biopsy specimen in 585 of 1283 cases (45.6%) proved lung cancer before lobectomy, whereas lobectomy proceeded in 698 cases (54.4%) without a diagnosis. Final pathology proved lung cancer in 90% (628 of 698) without a diagnosis before lobectomy and nonmalignant disease in 10% (70 of 698). Nonneoplastic pathology included granulomas (30 of 70 [43%]), pneumonia (12 of 70 [17%]), bronchiectasis (7 of 70 [10%]), and other lesions (21 of 70 [30%]). Operative mortality was 0.94% (25 of 2651) for the cohort and 1.0% (7 of 698) for diagnostic lobectomy only. Multivariate analysis identified patient age, type of lobectomy (right middle lobe), and the intermediate study tercile as associated with diagnostic lobectomy. CONCLUSIONS: Lobectomy for suspected lung cancer without diagnosis is common, represents practice variation, and infrequently (10% diagnostic, 2.6% all lobectomies) removes nonmalignant disease. Tissue confirmation before lobectomy is preferred, particularly when operative risk is increased. Diagnostic lobectomy is acceptable in carefully selected patients and lesions.

B cell-dependent subtypes and treatment-based immune correlates to survival in stage 3 and 4 lung adenocarcinomas.

Lung cancer is the leading cause of cancer-related deaths worldwide. Surgery and chemoradiation are the standard of care in early stages of non-small cell lung cancer (NSCLC), while immunotherapy is the standard of care in late-stage NSCLC. The immune composition of the tumor microenvironment (TME) is recognized as an indicator for responsiveness to immunotherapy, although much remains unknown about its role in responsiveness to surgery or chemoradiation. In this pilot study, we characterized the NSCLC TME using mass cytometry (CyTOF) and bulk RNA sequencing (RNA-Seq) with deconvolution of RNA-Seq being performed by Kassandra, a recently published deconvolution tool. Stratification of patients based on the intratumoral abundance of B cells identified that the B-cell rich patient group had increased expression of CXCL13 and greater abundance of PD1+ CD8 T cells. The presence of B cells and PD1+ CD8 T cells correlated positively with the presence of intratumoral tertiary lymphoid structures (TLS). We then assessed the predictive and prognostic utility of these cell types and TLS within publicly available stage 3 and 4 lung adenocarcinoma (LUAD) RNA-Seq datasets. As previously described by others, pre-treatment expression of intratumoral 12-chemokine TLS gene signature is associated with progression free survival (PFS) in patients who receive treatment with immune checkpoint inhibitors (ICI). Notably and unexpectedly pre-treatment percentages of intratumoral B cells are associated with PFS in patients who receive surgery, chemotherapy, or radiation. Further studies to confirm these findings would allow for more effective patient selection for both ICI and non-ICI treatments.

Surgery and proton radiation therapy for pediatric base of skull chordomas: Long-term clinical outcomes for 204 patients.

BACKGROUND: Data on clinical outcomes for base of skull (BOS) chordomas in the pediatric population is limited. We report patient outcomes after surgery and proton radiotherapy (PRT). METHODS: Pediatric patients with BOS chordomas were treated with PRT or combined proton/photon approach (proton-based; for most, 80% proton/20% photon) at the Massachusetts General Hospital from 1981 to 2021. Endpoints of interest were overall survival (OS), disease-specific survival, progression-free survival (PFS), freedom from local recurrence (LC), and freedom from distant failure (DC). RESULTS: Of 204 patients, median age at diagnosis was 11.1 years (range, 1-21). Chordoma location included 59% upper and/or middle clivus, 36% lower clivus, 4% craniocervical junction, and 1% nasal cavity. Fifteen (7%) received pre-RT chemotherapy. Forty-seven (23%) received PRT, and 157 (77%) received comboRT. Median total dose was 76.7 Gy (RBE) (range, 59.3-83.3). At a median follow-up of 10 years (interquartile range, 5-16 years), 56 recurred. Median OS and PFS were 26 and 25 years, with 5-, 10-, and 20-year OS and PFS rates of 84% and 74%, 78% and 69%, and 64% and 64%, respectively. Multivariable actuarial analyses showed poorly differentiated subtype, radiographical progression prior to RT, larger treatment volume, and lower clivus location to be prognostic factors for worse OS, PFS, and LC. RT was well tolerated at a median follow-up of 9 years (interquartile range, 4-16 years). Side effects included 166 patients (80%) with mild/moderate acute toxicities, 24 (12%) patients with late toxicities, and 4 (2%) who developed secondary radiation-related malignancies. CONCLUSION: This is the largest cohort of BOS chordomas in the literature, pediatric and/or adult. High-dose PRT following surgical resection is effective with low rates of late toxicity.

Giant Cell Arteritis Presenting With Multiple Cranial Neuropathies - Case Report.

Background: Vision loss accounts for most ophthalmic presentations of giant cell arteritis (GCA), but an important minority of patients present with diplopia and other cranial neuropathies. Case study: Here we present the case of an 84-year-old woman with a prior history of multiple cancers who was admitted to our hospital after developing double vision. She was found to have mydriasis, ptosis, and ophthalmoplegia in the right eye (OD) consistent with a combined R CNIII/CNVI neuropathy, as well as highly elevated inflammatory markers. Given her cancer history, the patient was initially worked up for various neoplastic, paraneoplastic, inflammatory, and infectious causes of multiple cranial neuropathies; however, as these results were negative, GCA became a more likely contender as a possible rare cause of multiple cranial neuropathies. The patient underwent temporal artery biopsy which showed pathology consistent with giant cell arteritis, and she was treated with steroids with eventual improvement in ophthalmoplegia and ptosis. Conclusions: This case illustrates the importance of recognizing GCA as a rare possible cause of multiple cranial neuropathies, including the indispensable role of temporal artery biopsy.