Faculty Bibliography

Objective/UNASSIGNED:Tumor-induced osteomalacia (TIO) is a rare osteomalacia characterized by paraneoplastic secretion of fibroblast growth factor 23. Concomitant occurrence of TIO during pregnancy is rarer still. Our objective was to report a young patient with debilitating fractures diagnosed with TIO who became pregnant and subsequently had her tumor localized by gallium-68 (Ga-68) DOTATATE positron emission tomography/magnetic resonance imaging (PET/MRI). Case Report/UNASSIGNED:A 28 year-old woman with a 2-year history of stress fractures was found to have the following: (1) alkaline phosphatase level, 220 (reference range, 30-95) U/L; (2) phosphorus level, 2.1 (2.5-5.0) mg/dL; (3) 1,25-dihydroxyvitamin D3 level, <8 (18-72) pg/mL; (4) 24-hour urine phosphorus level, 0.5 (0.3-1.3) g; and (5) fibroblast growth factor 23 levels, 1241 (reference range, <180) RU/mL. The patient became pregnant, and at term, a cesarean delivery was performed. Ga-68 DOTATATE PET/MRI showed a 9-mm intracortical mass in the right fibular head and right femoral and bilateral calcaneal stress fractures. The fibular lesion was resected; pathology showed a 1.5-cm lesion with positive fibroblast growth factor receptor 1 staining. Discussion/UNASSIGNED:This patient with TIO had an uneventful pregnancy and delivery. TIO is typically caused by benign mesenchymal tumors. Ga-68 DOTATATE PET/computed tomography has been used for localizing tumors causing TIO, yet MRI has superior contrast resolution over computed tomography. Therefore, it is not surprising that Ga-68 PET/MRI successfully localized this patient's tumor to the intracortical space of the fibular head and distinguished it from insufficiency fractures. Conclusion/UNASSIGNED:To our knowledge, this is the first report of phosphate treatment in a pregnant patient with TIO and the first report of a tumor-inducing TIO being localized by Ga-68 DOTATATE PET/MRI.

OBJECTIVES/OBJECTIVE:To evaluate whether a follow-up magnetic resonance imaging (MRI) scan performed after initial ultrasound (US) to evaluate soft tissue mass (STM) lesions of the musculoskeletal system provides additional radiologic diagnostic information and alters clinical management. METHODS:A retrospective chart review was performed of patients undergoing initial US evaluations of STMs of the axial or appendicular skeleton between November 2012 and March 2019. Patients who underwent US examinations followed by MRI for the evaluation of STM lesions were identified. For inclusion, the subsequent pathologic correlation was required from either a surgical or image-guided biopsy. Imaging studies with pathologic correlations were then reviewed by 3 musculoskeletal radiologists, who were blinded to the pathologic diagnoses. The diagnostic utility of MRI was then assessed on the basis of a 5-point grading scale, and inter-reader agreements were determined by the Fleiss κ statistic. RESULTS:Ninety-two patients underwent MRI after US for STM evaluations. Final pathologic results were available in 42 cases. Samples were obtained by surgical excision or open biopsy (n = 34) or US-guided core biopsy (n = 8). The most common pathologic diagnoses were nerve sheath tumors (n = 9), lipomas (n = 5), and leiomyomas (n = 5). Imaging review showed that the subsequent MRI did not change the working diagnosis in 73% of cases, and the subsequent MRI was not considered to narrow the differential diagnosis in 68% of cases. There was slight inter-reader agreement for the diagnostic utility of MRI among individual cases (κ = 0.10) between the 3 readers. CONCLUSIONS:The recommendation of MRI to further evaluate STM lesions seen with US frequently fails to change the working diagnosis or provide significant diagnostic utility.

There are few reported cases of non-Hodgkin's lymphoma metastasis to bone in the lower extremities. The authors present a case of cutaneous B-cell lymphoma thought to be in remission, with metastasis to the first metatarsal head with involvement in the synovial tissue of the first metatarsophalangeal joint. Following excision of the lesion, no further treatment was determined to be necessary. The patient was to be observed for local recurrence.

To the best of the authors' knowledge, this is the first published case of monophasic synovial sarcoma (SS) initially diagnosed as Ewing's sarcoma (ES), yet successfully treated with chemotherapy in a 24-year-old patient. The initial diagnosis showed a monotonous round cell tumor and positivity for CD99, characteristic of ES; however, the cytology was negative for the classic EWSR1 rearrangement of ES. The patient was treated with the standard chemotherapy protocol of ES - COG AEWS1031 Regimen A with vincristine, doxorubicin, cyclophosphamide, and mesna - as well as with wide resection. Post-resection tissue submission showed additional morphologic features which led to a re-evaluation of the classification of the tumor as well as additional molecular studies; these revealed positivity for translocations of SS18 (18q11.1) in 100% of the nuclei, which is most characteristic of SS, thus, reclassifying the neoplasm as a SS tumor. This case underscores the importance of considering several pathologic entities in the differential diagnosis of small, round blue cell tumors, including ES, SS, and lymphoma. It also demonstrates the importance of using chromosomal identification for a more definitive diagnosis, rather than relying on histological features and markers which are found in more than one tumor classification. There is conflicting evidence of the impact of chemotherapy on survival in SS, as it is primarily treated with radiation therapy. Since SS is rare, prospective studies on the effect of chemotherapy on survival are limited in number. However, our case study demonstrates that chemotherapy is another modality that can be used in the treatment of SS neoplasms.

Ultrasound-guided hookwire localization was initially introduced to facilitate the excision of nonpalpable breast lesions by guiding surgical exploration, thereby reducing operative time and morbidity. The same technique has since found utility in a range of other applications outside breast and can be useful within the musculoskeletal system. Despite this, there remains limited literature with respect to its technical aspects and practical utility. We describe our technique and a series of preoperative ultrasound-guided wire localizations in the musculoskeletal system to assist surgical excision of 4 soft tissue masses.

Adenomyoepitheliomas (AMEs) of the breast are uncommon and span the morphologic spectrum of benign, atypical, in situ, and invasive forms. In exceptionally rare cases, these tumors metastasize to regional lymph nodes or distant sites. In the era of genomic characterization, data is limited regarding AMEs. The aim of this study was to provide insight into the molecular underpinnings of a spectrum of AMEs. Seven cases of AMEs of the breast (benign-1, atypical-2, in situ-1, invasive-3) were identified in our files. The seven samples were interrogated using the Oncomine Comprehensive Assay v3 (ThermoFisher). Two atypical AMEs and the malignant in situ AME harbored the same gain-of-function PIK3CA mutation. The malignant in situ AME also showed EGFR amplification, not described previously. Both a benign AME and a malignant invasive AME shared the same gain-of-function AKT1 variant. The benign AME also showed a GNAS mutation. Moreover, the same gain-of-function HRAS mutation was present in an atypical AME and a malignant invasive AME. We also identified co-occurring HRAS and PIK3CA mutations in an ER-positive atypical AME, which has not been previously described. No fusion drivers were detected. We describe the molecular characteristics of the spectrum of AME tumors of the breast, which harbor alterations in the PI3K/AKT pathway. Our findings are clinically relevant with respect to the current options of targeted therapy in the rare instances where malignant AME tumors of the breast progress.

Thus far, only a single case describing an atypical appearance of elastofibroma dorsi at a prior thoracotomy site has been published in the literature. We describe a series of three cases recently imaged at our institution with the same atypical appearance, in order to highlight and increase recognition of this more unusual morphology in post-operative patients.

Here we present a case of a 38 year old male with an incidentally found right upper lobe lung mass. The patient underwent thoracoscopic resection of the mass which revealed a myxoid spindle cell lipoma. This is an exceedingly rare location for this tumor biology and here we discuss its pathological features and treatment options.

OBJECTIVE:To present the clinical, radiologic, and pathologic findings of a patient with carotid intimal sarcoma. METHODS:Detailed medical interview, neurologic examination, and diagnostic evaluation including CT angiography head and neck, MRI brain and neck, digital subtraction angiography, and biopsy of the mass were performed. RESULTS:We report a patient who presented with symptoms of multifocal, bilateral strokes over weeks caused by an enlarging tumor thrombus associated with an intimal sarcoma of the carotid artery. The presence of a carotid space mass encasing the left internal carotid artery was initially not recognized on imaging and was mistakenly attributed to soft atheromatous plaque rather than tumor thrombus. Rapid disease progression resulted in multiple intracranial metastases from tumor embolization. CONCLUSION/CONCLUSIONS:Clinical and radiologic findings of intimal sarcoma may be similar to those of thrombotic disease. However, patients with sarcoma may show an associated perivascular soft tissue mass and an unusual distribution of vessel stenosis. Reevaluation of imaging should be considered in patients presenting with initial imaging findings suggestive of rapidly progressive thrombotic disease who have a poor response to antithrombotic therapy and do not follow an expected clinical course.

A 72-year-old woman who presented with right-sided epiphora and conjunctivitis underwent a probing and irrigation procedure with normal results. She improved with antibiotic-steroid drops. A swelling in the medial canthal region completely resolved. One year later, she returned with symptoms of dacryocystitis. An external dacryocystorhinostomy was performed. Characteristic dacryoliths were removed from the sac lumen, and biopsy of the sac wall showed spicules of lamellar bone within a fibrous stroma. Diagnosed as fibrous dysplasia of the lacrimal sac, this rare entity represents the second such case in the literature.