Carcinoma Presenting Research Articles

Unusual Presentation of Papillary Thyroid Carcinoma as a Lateral Neck Cystic Mass: A Case Report

Unusual Presentation of Papillary Thyroid Carcinoma as a Lateral Neck Cystic Mass: A Case Report

Upper Extremity Mass as First Presentation of Metastatic Urothelial Carcinoma.

A 77-year-old woman presented with metastatic urothelial carcinoma as an elbow mass. To our knowledge, this is only the third reported case of urothelial carcinoma metastasizing to the upper extremity. The presence of metastatic disease at the time of diagnosis of urothelial carcinoma is rare, with metastases to the upper extremities even less common. This case is interesting given that the mass occurred after a direct trauma, causing a delay in diagnosis. It highlights the importance of a multidisciplinary oncology approach, and the need for more research to understand the biology of metastases. [Orthopedics. 202x;4x(x):xx-xx.].

Central sleep apnea as an initial presentation of small cell lung carcinoma with anti-Hu antibody-related paraneoplastic neurologic syndrome.

Anti-Hu antibody-related paraneoplastic neurologic syndrome (PNS), a rare disease primarily associated with small cell lung carcinoma, is characterized by diverse neurologic manifestations. Central sleep apnea, although rare, is specific to anti-Hu antibody-related PNS. Herein, we present a case of out-of-hospital cardiac arrest attributed to hypercapnic central sleep apnea and detail the subsequent workup that revealed anti-Hu brainstem encephalitis. A malignancy survey revealed mediastinal small cell carcinoma. The patient was treated by tumour excision, chemotherapy, plasma exchange, and high-dose glucocorticoids. Though the neurologic damage caused by anti-Hu antibody was documented to be relatively irreversible in literatures, such hypercapnic central sleep apnea resolved in our case about 1 month later.

A case of sigmoid colon carcinoma presenting as pyrexia of unknown origin

Pyrexia of unknown origin (PUO) is a diagnostic challenge with a variety of causative factors, one of which is malignancy. This report throws light on sigmoid colon carcinoma, one of the lesser understood causes of pyrexia of unknown origin, where unremitting fever was the presenting symptom. Exclusion of common infectious causes of fever with thorough diagnostic work up lead to a diagnosis of adenocarcinoma of sigmoid colon. Fever subsided completely in the postoperative course.

Isolated Cystic Neck Mass as Only Presentation of Tonsillar Carcinoma

Isolated Cystic Neck Mass as Only Presentation of Tonsillar Carcinoma

Adrenal Cortical Carcinoma Presenting as CSCR.

We describe a case of bilateral chronic central serous chorioretinopathy (CSCR) secondary to adrenal cortical carcinoma. Case report of a 70-year-old Hispanic man presenting with bilateral multifocal CSCR. Clinical findings of bilateral chronic CSCR along with 160 µm of subretinal fluid (SRF) and choroidal thickness greater than 400 µm without enhanced depth optical coherence tomography was noted in a patient presenting with distortion in vision in both eyes and weight gain of 15 pounds, weakness, and fatigue starting 8 months prior. Further endocrine testing showed an elevated 24-hour urinary free cortisol level of 137 µg with no change in serum cortisol levels following low-dose dexamethasone suppression test and undetectable serum adrenocorticotropic hormone (ACTH) levels consistent with ACTH-independent Cushing's syndrome. Imaging of the abdomen revealed heterogeneously enhancing masses, and biopsy of the adrenal tumor led to the diagnosis of adrenal cortical carcinoma. He died 3 weeks after starting hospice care, and only completed one round of chemotherapy. Adrenal tumors including adrenal cortical carcinoma may present as bilateral chronic central serous chorioretinopathy.

Pigmented Syringomatous Carcinoma/Sweat Gland Carcinoma of the Vulva With Melanocytic Colonization: An Uncommon Presentation of a Rare Sweat Gland Neoplasm

Abstract: Primary vulvar carcinomas are rare and constitute a diverse group of neoplasms. These primary tumors are typically classified based on their presumed tissue of origin or histological characteristics. Among these, carcinomas of sweat gland origin are particularly significant. They closely resemble similar malignancies in nonvulvar skin, including various cutaneous adnexal-type cancers such as apocrine and eccrine adenocarcinomas. Syringomatous carcinoma of the vulva is a rare malignant sweat gland neoplasm known for its infiltrative growth and tendency for local recurrence. Typically, these malignancies manifest as nonulcerated nodules or plaques, primarily in the head and neck region. The occurrence of syringomatous carcinoma in the vulvar region is exceptionally rare. Herein, we present a unique case of a 35-year-old woman with a dark mole measuring 1.5 × 1.0 cm on the vulva. Complete excision was performed to exhibit an infiltrative haphazard proliferation of elongated ductules and tubules, displaying significant cytologic atypia characterized by irregular nuclear contours and variably prominent nucleoli. Extensive melanocytic pigment deposition and stromal fibrosis were also observed. Immunohistochemical staining demonstrated positive expression of epithelial markers, including keratins (AE1/AE3) and epithelial membrane antigen, supporting the diagnosis of syringomatous carcinoma. CK7 and carcinoembryonic antigen were negative, whereas SOX10 and pan melanin highlighted admixed, cytologically bland melanocytes within the epidermis and neoplastic nests. This case represents a highly unusual presentation of syringomatous carcinoma associated with melanocyte colonization. Due to limited data on the optimal management strategies, a multidisciplinary approach involving gynecologic oncologists, dermatopathologists, and radiation oncologists is essential for treatment decisions. Long-term follow-up is crucial, considering the potential for local recurrence and metastatic spread, emphasizing the importance of comprehensive clinical management for favorable patient outcomes of this rare malignancy.

Breast Neuroendocrine Carcinoma Discovered by Lymph Node and Osteomedullary Metastasis: A Case Report

This case highlights a rare presentation of small cell mammary neuroendocrine carcinoma in a young woman, with metastatic spread to the spinal cord. Such a presentation is exceptionally uncommon, particularly in this demographic, and underscores the diagnostic challenges associated with neuroendocrine tumors outside typical locations. Reporting this case adds to the limited literature on mammary neuroendocrine carcinoma with spinal metastasis and may guide early identification in similar cases. We report A 20-year-old female patient 3 with persistent lower back pain over three months. Clinical examination revealed cervical lymphadenopathy and bilateral breast masses. Magnetic resonance imaging (MRI) identified a spinal tumor infiltration. A biopsy of the cervical lymph nodes, followed by immunohistochemical analysis, confirmed the diagnosis of small cell mammary neuroendocrine carcinoma. Chemotherapy was chosen as the primary therapeutic approach, given the tumor’s aggressiveness and advanced stage at diagnosis. This case underscores the importance of considering neuroendocrine carcinoma as a differential diagnosis for young patients presenting with atypical tumor localizations, such as bilateral breast masses and spinal metastasis. The case highlights the necessity of a multidisciplinary approach in diagnosing and managing rare tumors and demonstrates the potential impact of prompt recognition and treatment to improve outcomes.

A case series on parathyroid carcinoma: Diagnostic challenges and therapeutic approaches

IntroductionParathyroid carcinoma is an exceptionally rare endocrine malignancy, constituting <1 % of primary hyperparathyroidism (PHPT) cases. It presents with more severe hypercalcemia and higher PTH levels than benign parathyroid diseases, requiring increased clinical awareness for accurate identification and specialized management. The results of this case series may provide insight into the clinical presentation, diagnostic workup, surgical management, and prognosis of parathyroid carcinoma, supplemented by a comprehensive review of current diagnostic and therapeutic approaches. MethodsWe retrospectively reviewed three cases of parathyroid carcinoma treated at a tertiary referral hospital. We analyzed patient demographics, clinical presentation, imaging studies, surgical interventions, histopathological findings, and follow-up data. We emphasized intraoperative decisions, criteria for achieving sustained hormonal control, and long-term monitoring protocols. ResultsPatient 1: An 84-year-old male patient presented with severe hypercalcemia and elevated PTH levels. Preoperative imaging, including 4D CT and sestamibi scan, identified a 3.7 cm, 9.32-gram parathyroid mass, which was surgically resected. Despite removing the mass and normalizing calcium levels, PTH levels remained elevated, suggesting residual disease.Patient 2: A 77-year-old male patient with osteoporosis and a history of kidney stones underwent presurgical parathyroid scintigraphy, which indicated a right superior parathyroid adenoma. A 3 cm, 3.55-gram parathyroid carcinoma was successfully removed, normalizing calcium and PTH levels. Follow-up imaging and labs confirmed no recurrence.Patient 3: A 61-year-old female patient with end-stage renal disease presented with a 5 cm hypervascular neck mass. Preoperative 4D CT and ultrasound suggested an adenoma. After surgery, PTH levels normalized, but the patient died five years later from an unrelated stroke. ConclusionParathyroid carcinoma is a rare malignancy that demands thorough diagnostic procedures, imaging techniques, precise surgical intervention, and vigilant long-term follow-up to manage the risk of recurrence. Elevated PTH and calcium levels should raise suspicion of malignancy, especially in severe hypercalcemia. This case series illustrates how the disease can present variably, with unique challenges in each patient. Despite the limitations of current adjuvant therapies, advancements in genetic and molecular research hold promise for future therapeutic options.

Metastatic renal cell carcinoma presenting as gastrointestinal bleeding.

A 73-year-old female with metastatic renal cell carcinoma (RCC) presented with melena and lethargy. She was found to be iron deficient with a hemoglobin of 101 g/L. Her gastroscopy found six irregular pedunculated non-bleeding polyps, 10-20 mm in diameter. Histopathology of the resected polyp returned as metastatic clear cell renal cell carcinoma. Gastric metastases from any primary malignancy are rare and metastatic RCC accounts for only 7% of these tumors. Furthermore, while RCC commonly metastasises to the lung, bone and lymph nodes, metastasis to the gastrointestinal tract is extremely rare, occurring in <1% of patients. Presentation of RCC as a gastric polyp is usually a late event, and on average occurs 6.7 years after initial diagnosis of RCC. Therefore, this case highlights a rare but important late complication of RCC, presenting as gastrointestinal bleeding secondary to gastric metastases.

P25 When fevers hide secrets: a case report of papillary thyroid carcinoma presenting as secondary haemophagocytic lymphohistiocytosis

P25 When fevers hide secrets: a case report of papillary thyroid carcinoma presenting as secondary haemophagocytic lymphohistiocytosis

Progressive Unilateral Proptosis and [18F]FDG-Avid Lesions Connoting Aggressive Disease in Radioiodine-Refractory Differentiated Thyroid Carcinoma

AbstractRadioiodine-refractory differentiated thyroid carcinoma (RAIR-DTC) have poor prognosis as compared with radioiodine concentrating thyroid carcinoma. We present a case of follicular thyroid carcinoma presenting as a disseminated disease initially, underwent thyroid surgery and radioiodine (RAI) therapy. Following RAI, the patient developed a sudden-onset unilateral proptosis, finally diagnosed as orbital metastasis. [18F]-Fluorodeoxyglucose (FDG)-positron emission tomography-computed tomography identified FDG-avid metastatic lesions more numerous than the RAI-avid lesions. The patient was treated with local and systemic targeted therapy, but despite these treatments, he developed progressive disease indicating aggressive nature of the disease consistent with [18F]FDG-avid RAIR-DTC.

Rare Presentation of Anaplastic Carcinoma as a Mural Nodule in Mucinous Cystadenoma with Concurrent Benign Brenner Tumor

Abstract Introduction/Objective Mural nodules in ovarian mucinous tumors, particularly which are anaplastic carcinomas, represent an exceedingly rare and complex diagnostic category. The literature documents only a few such tumors, predominantly sarcoma-like, with favorable prognoses. In contrast, malignant mural nodules, including anaplastic carcinoma and sarcomatous or carcinosarcomatous types, are notably rare, with fewer than ten cases reported. The co-occurrence of an anaplastic carcinoma mural nodule with a benign Brenner tumor presents distinct diagnostic and treatment complexities stemming from mixed tumor pathology and associated genetic mutations like KRAS and p53, critical in the development of these unusual nodules. This report deepens our insight into rare ovarian tumors. Methods/Case Report A 60-year-old woman with persistent lower abdominal pain underwent surgery for a suspected benign ovarian cyst based on initial imaging. The removed ovary contained a 10.5 x 10 x 8 cm unilocular cyst lined with benign, mucin-containing columnar epithelium. However, a 2 cm anaplastic carcinoma mural nodule was identified within the cyst, exhibiting cellular pleomorphism, nuclear atypia, and high mitotic activity. Immunohistochemical staining confirmed the carcinoma with diffuse cytokeratin and EMA positivity. The fallopian tube was free of tumor involvement, and no capsular or lymphovascular invasion was seen. The cancer was staged as PT1a, pNx, pMx. Results (if a Case Study enter NA) NA Conclusion Anaplastic carcinoma, when present as a mural nodule within a benign-looking mucinous cystadenoma, demands an aggressive treatment strategy due to its poor prognosis and aggressive nature. Such cases require a deviation from standard benign treatment protocols to include extensive surgery, possibly, depending on disease progression, chemotherapy or radiation.

Uncommon Presentation of Pulmonary Adenoid Cystic Carcinoma: A Case of Brain Metastasis in a Young Smoker

Abstract Introduction/Objective Pulmonary adenoid cystic carcinoma (PACC) is a rare entity, accounting for only 0.04-0.2% lung cancers, and mainly originating from the small salivary glands in the tracheobronchial tree. Due to slow-growing pattern and unspecific symptoms, the diagnosis is often delayed. While metastasis in PACC is uncommon, reports of brain metastasis are exceedingly rare. We present a case of PACC with metastasis to the brain in a young smoker. Methods/Case Report A 29-year-old female with history of smoking presented with headache, hypersomnia, episodes of vomiting and falling. Physical examination revealed multiple palpable nodes on the mid head, left temporal and right parietal area, left shoulder area were found. CT scan demonstrated complex cystic mass with a mural nodule within the left cerebellar hemisphere, with displacement of the cerebellar tonsils, as well as a 7.4 cm left infrahilar mass with heterogenous enhancement. Patient underwent craniotomy with tumor resection and left lower lobe endobronchial biopsy. Touch smear of the brain lesion showed clusters of hyperchromatic cells with myxoid like and hyalinized stroma. H&amp;E stain showed cords of neoplastic cells embedded in a basophilic/myxoid stroma. Lung biopsy showed similar histological patterns. IHC stain showed the tumor cells were positive for epithelial and myoepithelial cells markers(CAM5.2, CK7, p63, Sox 10), retained INI1/BAF47 and BRG1 expression, negative for NUT and BCOR. Salivary Gland NGS Fusion Panel was performed and detected a MYBL1::NFIB [t(8;9)(8q13.1;9p23)] fusion alteration, which confirmed the diagnosis of adenoid cystic carcinoma. Considering no lesion was found in the patient’s head and neck, diagnosis of PACC was made. Results (if a Case Study enter NA) NA Conclusion PACC manifests three histologic subtypes: cribriform (most common), trabecular, and solid. In this case, brain and lung lesions exhibited similar patterns - nests of small, monomorphic cells within a myxoid-like and basophilic stroma background, consistent with trabecular pattern. Cytologically, densely packed cellular clusters were embedded in a myxoid like matrix. Distinguishing PACC from other salivary gland tumors is challenging. Immunostains for epithelial and myoepithelial cells, along with morphology, aid in diagnosis. The MYB::NFIB fusion helps differentiate from other lung salivary gland malignancies, but is found in a lower percentage of PACC cases (~40%) compared to other primary adnoid cystic carcinoma (~85%).

All that is squamoid is not squamous: A rare case of Squamoid Eccrine Ductal Carcinoma presenting as an intranasal mass

Abstract Introduction/Objective Squamoid eccrine ductal carcinoma (SEDC) is a rare adnexal tumor that poses diagnostic challenges because of the rarity, variable clinical presentation, and misdiagnosis on superficial biopsy sampling. Methods/Case Report We report a 52-year-old immunosuppressed male, status-post kidney and heart transplants who presented with an anterior nasal mass, the biopsy of which was interpreted as squamous cell carcinoma (SCC). Resection revealed a 2.5cm intranasal mass eroding through the hard palate. Histology showed a biphasic tumor arising from nasal vestibular skin with a superficial squamoid component (p40 positive) and a deeply invasive component demonstrating ductal differentiation (CEA positive) consistent with SEDC. SEDC has a predilection towards skin of head and neck region but SEDC presenting as an intranasal mass has not been reported. In our case, the tumor arose from nasal vestibular skin with destructive bony invasion within the nasal cavity. The patient’s long- term immunosuppression likely played a role in the etiopathogenesis and aggressive progression of this tumor. Interestingly, he also had history of multiple sebaceous carcinomas and cutaneous T-cell lymphoma with no known genetic predisposition, further implicating immunosuppression as the key risk factor for development of his cutaneous malignances. Results (if a Case Study enter NA) N/A Conclusion This case exemplifies the potential diagnostic pitfalls in squamoid lesions of the head and neck. Given the overwhelming prevalence of conventional SCC, rarer tumors with squamous differentiation often are not considered in the differential diagnosis, especially of an intranasal mass. A superficial biopsy often is misdiagnosed as SCC due to the lack of representation of deep-seated ductal components. A high index of suspicion and adequate examination of deeper aspects of the lesion are imperative for accurate diagnosis.

Paraneoplastic Neuromyelitis Optica Associated with Renal Cell Carcinoma Presenting with Tumefactive Demyelination Lesions

Paraneoplastic Neuromyelitis Optica Associated with Renal Cell Carcinoma Presenting with Tumefactive Demyelination Lesions

7159 Brown Tumor As Primary Presentation Of Parathyroid Carcinoma In A Young Female

Abstract Disclosure: S.G. Zachariah: None. R. Anand: None. B.Y. Wong: None. H.J. Lee: None. Title Brown Tumor as Primary Presentation of Parathyroid Carcinoma in a Young Female Introduction/Background: Parathyroid carcinoma (PC) is a rare cause of hyperparathyroidism (HPT) accounting for less than 1% of primary HPT cases. The mean age of PC presentation is 62 years. Long-standing HPT can lead to the formation of osteitis fibrosis cystica (brown tumors). In today’s world of advanced screening, they are an increasingly rare presentation of HPT. We present a case of PC presenting as multiple brown tumors in a young woman. Case: A previously healthy 32-year-old woman presented to the emergency department with right shoulder pain after a mechanical fall. MRI revealed multiple osseous lesions of the proximal humerus, glenoid, and scapula, concerning for possible metastatic malignancy. Notable labs: calcium 13.6 mg/dL [8.5 - 10.5 mg/dL], phosphorus 1.7 mg/dL [2.5 - 4.5 mg/dL], alkaline phosphatase 2,369 U/L [&amp;lt; 130 U/L], 25-OH vitamin D 0.8 ng/mL [30 - 60 ng/mL], and parathyroid hormone greater than 2,500 pg/mL [20-80 pg/mL]. Albumin and renal function were normal. CT chest/abdomen/pelvis showed lytic lesions of the left 7th rib, anterior superior iliac spine (with nondisplaced fracture), pelvis, and sacrum. Subsequent pelvic biopsy showed fragmented bony trabeculae with osteoblastic rimming and rare osteoclasts, fragments of fibrous tissue with few plasma cells and hemosiderin laden macrophages, possibly consistent with brown tumor. On parathyroid ultrasound, a 2.2 cm cystic mass was seen along the left common carotid artery. CT neck confirmed the location and also reported C7-T1 spinal lesions. Calcium levels stabilized with IV fluids and 90 mg IV pamidronate. She underwent a left parathyroidectomy and left hemithyroidectomy with central neck dissection. Pathology was consistent with a low-grade parathyroid carcinoma, with a foci of angioinvasion and capsular invasion without lymph node metastases. The Ki-67 index was less than 1%. Post-operatively, the patient was started on calcium and calcitriol supplementation and did not experience hungry bone syndrome. On further discussion, the patient noted that she had a jaw tumor that was previously biopsied and found to be benign. The patient has since been referred for genetic testing. Conclusion/Clinical Lessons: Both PC and its initial presentation with brown tumors are uncommon. Even more rare is the presentation of both in a young, otherwise healthy female. In this context, it is also important to note that brown tumors can mimic osseous metastases and appropriate biochemical, imaging, and histopathological evaluation is needed. The diagnosis of PC under 40 years of age is uncommon and genetic testing is indicated. Syndromes including multiple endocrine neoplasia type 1, familial isolated hyperparathyroidism, and hyperparathyroidism-jaw tumor syndrome are potential causes of inherited PC. Presentation: 6/3/2024

8385 Coexistence of Parathyroid Adenoma &amp; Papillary Thyroid Cancer: A Rare Case Report

Abstract Disclosure: K. Dash: None. S. Verma: None. U. Ayyagari: None. M. Roy: None. S. Rathore: None. Prevalence of primary hyperparathyroidism (pHPT) ranges from 0.1- 0.4% in general population. Nodular thyroid disease is an increasingly common incidental diagnosis due to widespread use of ultrasound. Papillary thyroid cancer (PTC) is the most common cancer of thyroid gland. Here we report a 53 year old post-menopausal woman presented with weight loss, generalised body aches, arthralgia, myalgia, and proximal muscle weakness. She was hypertensive and clinically euthyroid. Physical examination revealed generalized tenderness all over the body but no thyroid or parathyroid nodules on palpation. Biochemical evaluation showed hypercalcemia 12.1mg/dl (8.4-10.2mg/dl), PTH&amp;gt;2000pg/ml (14-72pg/ml), ALP-1855 U/L (40–125 U/L), decreased phosphorous of 2.4mg/dl (25-4.6 mg/dl), and vitamin-D of 46 nmol/L ( 75-250 nmol/L). USG neck revealed a heterogeneous lesion at the lower pole of right lobe of thyroid gland &amp; two small hypoechoic nodules seen in the right lobe of thyroid gland. FNAC from nodules was inconclusive. USG abdomen revealed nephrocalcinosis. DEXA scan showed severe osteoporosis. Tc99mSestamibi SPECT-CT showed uptake at lower pole of right lobe of thyroid. On exploration, two nodules were palpated in the right lobe of the thyroid and simultaneous right hemi-thyroidectomy was performed. Histopathologic report confirmed parathyroid adenoma (figure 1) as well as presence of carcinoma in the two nodules: one was a papillary thyroid cancer (Classic variant) and the other a follicular variant of papillary thyroid carcinoma (figure 2). Margins were negative for malignancy. She was treated with levothyroxine to maintain TSH &amp;lt;0.1U/L and followed up with annual ultrasound screening. At 2 year follow up, patient was symptom free with improved T score on DEXA scan and no nodule over residual thyroid gland. Discussion: Co-existence of pHPT and PTC ranges from 2.3-4.3%. The use of ultrasound neck as a routine imaging modality for localisation of parathyroid adenoma allows detection of thyroid nodules. Benign and/or malignant thyroid nodules are commonly seen in patients with pHPT and this can range from 2-15%. Women have higher risk for co-existence. The relationship between the two diseases is thought to be incidental. Some authors have suggested possible role of shared genes, embryological factors, transcription factors, vitamin-D deficiency and hyperparathyroidism that could lead to activation of angiogenic factors and carcinogenesis. Fig. 1. Parathyroid adenoma. (a)Tc99m sestamibi scan showing right inferior parathyroid adenoma (b) Parathyroid adenoma (400x high power) comprising predominantly of Chief cells with mild pleomorphism. Fig. 2. Histopathology of PTC. (a)Papillary Carcinoma thyroid. 10xPhotomicrograph showing areas of calcification. (b) Papillary Carcinoma thyroid. Photomicrograph showing thyroid with papillary pattern with areas of infiltration. Presentation: 6/1/2024

7191 When Pain Is Misdiagnosed: A Case of Parathyroid Carcinoma Masked as Fibromyalgia

Abstract Disclosure: H. Pham: None. P.V. Kumar: None. S. Taylor: None. Parathyroid carcinoma is a rare and aggressive cause of hyperparathyroidism, typically associated with &amp;lt;1% of primary hyperparathyroidism cases. Incidence occurs mainly in the 5th decade of life, with less than 4% of all cases presenting in patients under age 30. Here, we highlight a case involving a 28-year-old woman with fibromyalgia who presented for worsening right shoulder pain in the setting of progressive, poorly characterized pain for the past year. Her initial physical exam was unremarkable aside from a non-tender left sided neck enlargement. However, her laboratory results were significant for corrected serum calcium of 15 mg/dL, serum phosphorus of 2.3 mg/dL, parathyroid hormone (PTH) &amp;gt;2500 pg/mL, and alkaline phosphatase 1604 units/L. X-ray of her right shoulder demonstrated mottled bone concerning for degenerative disease. Thyroid ultrasound revealed a complex cystic lesion posterior to the left thyroid lobe measuring 5.3 x 3.9 x 2.9 cm, worrisome for giant parathyroid adenoma. CT abdomen/pelvis showed diffuse osteosclerosis and innumerable lytic lesions, consistent with osteitis fibrosa cystica, as well as bilateral nephrolithiasis, likely medullary nephrocalcinosis. Her hypercalcemia was treated with aggressive hydration with normal saline and IV pamidronate. She underwent surgical resection of her parathyroid adenoma, which was unfortunately complicated by symptomatic hypocalcemia requiring prolonged care in the ICU. Her calcium levels did improve within a few days, and she was subsequently discharged with close outpatient follow-up. Final pathology report showed predominant thickened trabecular growth pattern with focal vascular invasion consistent with parathyroid carcinoma. Our patient’s case represents a rare presentation of parathyroid carcinoma in a young patient without any additional risk factors. Although atypical, her severe symptomatic hypercalcemia, nephrolithiasis, presence of large neck mass, and diffuse skeletal disease warranted immediate concern for malignant hyperparathyroidism instead of benign adenoma. Delayed diagnosis in our patient led to prolonged bone disease and severe complications. While hungry bone syndrome typically manifests post-parathyroidectomy in patients with end-stage renal disease, our patient experienced this complication in the setting of advanced, untreated hyperparathyroidism. We should consider hypercalcemia and hyperparathyroidism in our differential diagnosis for chronic pain, especially if pain remains uncontrolled with conservative measures. The most appropriate initial test for evaluation of hypercalcemia is a PTH level to distinguish between PTH-dependent and PTH-independent etiologies. Parathyroid carcinoma, even in young patients, should be considered when PTH is &amp;gt;3x upper limit of normal, serum calcium is &amp;gt;14, or skeletal and renal involvement is present. Presentation: 6/3/2024

6702 Management And Complications Of Metastatic Adrenocortical Carcinoma Presenting With Severe Cushing Syndrome

Abstract Disclosure: S. Rodrigues: None. A.K. Sumal: None. Background: Metastatic adrenocortical carcinoma (ACC) presenting with Cushing syndrome (CS) is a complicated, aggressive disease that commonly requires multiple adrenal steroidogenesis inhibitors and chemotherapy to achieve hormonal and tumor control. Clinical Case: A 66-year-old man with a history of prostate cancer and hypertension presented with right flank and back pain, worsening type 2 diabetes, profound proximal muscle weakness, and 3+ lower extremity edema to his thighs. CT and PET-CT revealed a 10.9 cm right adrenal mass with pericaval lymphadenopathy and metastatic disease at the L2 vertebral body. Laboratory testing demonstrated evidence of hypercortisolism with elevated 24-hour urinary cortisol excretion (449 mcg/24h; n&amp;lt;45 mcg/24h), and abnormal 1 mg dexamethasone suppression test (cortisol 15 mcg/dL; n&amp;lt; 1.8 mcg/dL) with suppressed ACTH (&amp;lt;6 pg/mL; n=7-63 pg/mL). Surgical resection of the primary tumor was aborted intraoperatively given the discovery of new peritoneal metastases, which were confirmed by biopsy to be metastatic ACC. He was started on mitotane and osilodrostat to manage his severe CS. He was also started on dexamethasone, both to prevent adrenal insufficiency and to avoid influencing serum cortisol measurements used to assess disease control. However, given his significant peripheral edema and weakness, he was functionally unable to receive chemotherapy. Despite rapid uptitration of mitotane and osilodrostat over three weeks, his CS remained uncontrolled, and he was ultimately hospitalized for lower extremity paralysis and septic shock due to pyelonephritis. Repeat imaging revealed severe spinal canal stenosis from an L2 pathologic fracture, as well as worsening hepatic, osseous, peritoneal, and retroperitoneal metastases. After recovery from his septic shock, he was started on chemotherapy with carboplatin and etoposide while hospitalized, but his mitotane was intermittently held due to elevated transaminases. His hospital course was complicated by hypotension requiring pressor support, atrial fibrillation, hemoperitoneum, worsening anasarca, and acute kidney injury requiring continuous renal replacement therapy. Given his worsening condition that precluded him from further chemotherapy or palliative radiation, he elected to pursue comfort care measures and expired shortly thereafter. Conclusion: This case highlights the therapeutic challenges of metastatic ACC presenting with life-threatening CS. Simultaneous use of multiple adrenal steroidogenesis inhibitors is often required for control of hypercortisolism, and chemotherapy is equally necessary to manage tumor burden. However, as in this case, disease-related complications can limit treatment management and result in rapid deterioration. Thus, early diagnosis and prompt treatment of metastatic ACC presenting with CS is critical to prevent morbidity and mortality. Presentation: 6/3/2024