Swanson, Amy A.

Summary We report the case of a male patient with papillary thyroid cancer, familial thoracic aortic aneurysm and dissection, and a variation in the MYH11 gene. Because of considerable tumor bulk in the neck that was not resectable, the patient underwent partial resection at age 14 years. Since then, the patient has received only suppressive thyroid hormone therapy. He is now 71 years old, which is 57 years after the initial resection. The patient received care at our institution from July 2009 to August 2019, during which we documented the stability of multiple calcified masses in the neck. Follow-up examinations at another institution from September 2019 to April 2023 also confirmed the stability of the masses. The underlying cause of this unusually long indolent course of the disease is unclear. Whether extensive tumor calcifications or the MYH11 sequence variation contributed to the disease course is also uncertain. Learning points Papillary thyroid cancer with neck metastases may, in some cases, be stable and remain asymptomatic for decades. If locoregional stability of papillary thyroid cancer is documented for many years, observation may be preferable to extensive neck surgery in selected cases. This is the first report of an MYH11 gene alteration and thoracic aortic aneurysm in a patient with papillary thyroid cancer with indolent neck metastases. Future studies of MYH11 gene alterations in thyroid carcinoma are needed.

AbstractLymphangioleiomyomatosis (LAM) is a rare disease with variable presentations. The neoplastic cells in LAM demonstrate a unique and diagnostically important “myomelanocytic” phenotype. Cytologic reports of LAM are infrequent and have not in the past emphasized the floating island pattern in which circumscribed aggregates of lesional cells are rimmed by appliques of flattened endothelium. This case illustrates the cytology of LAM and emphasizes that the floating island cytoarchitectural pattern more classically associated with entities such as hepatocellular carcinomas may be seen in cytological preparations of LAM at unanticipated body sites.

The published literature on cervicovaginal cytology includes fewer than ten reported cases of Cokeromyces recurvatus identified in Pap test samples. We report a unique case of an asymptomatic 27-year-old female with persistent gynecologic tract colonization by C. recurvatus in which distinctive fungal microorganisms were identified in three samples collected over three consecutive years.

Abstract ALK-positive histiocytosis is a rare subtype of histiocytic neoplasm first described in 2008 in 3 infants with multisystemic disease involving the liver and hematopoietic system. This entity has subsequently been documented in case reports and series to occupy a wider clinicopathologic spectrum with recurrent KIF5B-ALK fusions. The full clinicopathologic and molecular spectra of ALK-positive histiocytosis remain, however, poorly characterized. Here, we describe the largest study of ALK-positive histiocytosis to date, with detailed clinicopathologic data of 39 cases, including 37 cases with confirmed ALK rearrangements. The clinical spectrum comprised distinct clinical phenotypic groups: infants with multisystemic disease with liver and hematopoietic involvement, as originally described (Group 1A: 6/39), other patients with multisystemic disease (Group 1B: 10/39), and patients with single-system disease (Group 2: 23/39). Nineteen patients of the entire cohort (49%) had neurologic involvement (7 and 12 from Groups 1B and 2, respectively). Histology included classic xanthogranuloma features in almost one-third of cases, whereas the majority displayed a more densely cellular, monomorphic appearance without lipidized histiocytes but sometimes more spindled or epithelioid morphology. Neoplastic histiocytes were positive for macrophage markers and often conferred strong expression of phosphorylated extracellular signal-regulated kinase, confirming MAPK pathway activation. KIF5B-ALK fusions were detected in 27 patients, whereas CLTC-ALK, TPM3-ALK, TFG-ALK, EML4-ALK, and DCTN1-ALK fusions were identified in single cases. Robust and durable responses were observed in 11/11 patients treated with ALK inhibition, 10 with neurologic involvement. This study presents the existing clinicopathologic and molecular landscape of ALK-positive histiocytosis and provides guidance for the clinical management of this emerging histiocytic entity.

Abstract We present a case report of a 25 year-old man with MELAS (Mitochondrial Encephalopathy, Lactic Acidosis, and Stroke-like episodes) syndrome, who died suddenly and unexpectedly from diabetic ketoacidosis. This case report illustrates why it is important for medical examiners to be familiar with the clinical and autopsy features of MELAS syndrome and to be aware of the common complications, which may lead to sudden unexpected death.

Abstract Adult spinal cord ependymomas are typically low grade and have a relatively favorable clinical course following gross total resection. We report 4 cases of anaplastic spinal cord ependymoma with MYCN amplification, an exceptionally rare finding. All cases occurred in the spinal cord of adolescent and young adult women and had morphological and immunohistochemical features of anaplastic ependymomas (World Health Organization grade III). Chromosomal microarray analysis demonstrated amplification of 2p24 (including MYCN) in all cases. One patient died 6 months after surgery. Another patient recently had removal of metastatic nodules in the thoracic region, following gross total resection and adjuvant radiation therapy of a lumbar ependymoma 1 year previously. One patient responded well after chemotherapy but died after multiple relapses 82 months after diagnosis. We found MYCN amplification reported in 2 other ependymomas, both anaplastic and arising in the spinal cord of adult females (Brain Pathol 2001;11:133–43). One patient had multiple recurrences in the spinal cord and an intracranial metastasis. Although MYCN amplification is rare in ependymomas, the current and previously reported cases suggest that this is associated with higher-grade histology, spinal location, and often unfavorable prognosis. The clinical significance and therapeutic implications of MYCN amplification in ependymomas require further evaluation.

AbstractCerebral amyloidomas, characterized by localized amyloid deposits in the nervous system in the absence of systemic disease, are rare. These typically consist of immunoglobulin light chain (AL)-type, predominantly lambda. Trigeminal nerve involvement is exceptionally rare with only 21 previously reported cases, three with bilateral disease. We report two additional cases of amyloid localized to Meckel’s cave with secondary involvement of the trigeminal nerves bilaterally, with protein characterization by mass spectrometry. The patients, both females, 39 and 49-years-old, respectively, presented with the insidious onset of progressive trigeminal neuropathy, including pain and numbness with sensory loss, refractory to medical therapy. One patient experienced bilateral symptoms. Magnetic resonance imaging demonstrated abnormal thickening and contrast enhancement along Meckel’s cave bilaterally in both cases. The clinical differential diagnosis included benign neoplasms and inflammatory disorders. At the time of biopsy, the trigeminal nerve was noted to be enlarged and multinodular in one case and associated with abnormal soft tan tissue in the other case. Microscopically, the nerve biopsies showed extensive Congo red-positive amyloid deposits. Liquid chromatography tandem mass spectrometry demonstrated that the amyloid was of (AL)-type in both cases (AL [kappa] in one case and AL [lambda] in the other). After extensive evaluation, there was no evidence of systemic involvement. Both patients received localized radiotherapy for their refractory symptoms. One patient has stable symptomatology and imaging. No follow-up is available for the other patient.