Background Naegleria fowleri is a climate-sensitive, thermophilic ameba found in warm, freshwater lakes and rivers. Primary amebic meningoencephalitis (PAM), which is almost universally fatal, occurs when N. fowleri–containing water enters the nose, typically during swimming, and N. fowleri migrates to the brain via the olfactory nerve. In August 2013, a 4-year-old child died of meningoencephalitis of unknown etiology in a Louisiana hospital. Methods Clinical and environmental testing and a case investigation were initiated to determine the cause of death and to identify potential exposures. Results Based on testing of CSF and brain specimens, the child was diagnosed with PAM. His only reported water exposure was tap water; in particular, tap water that was used to supply water to a lawn water slide on which the child had played extensively prior to becoming ill. Water samples were collected from both the home and the water distribution system that supplied the home and tested; N. fowleri were identified in water samples from both the home and the water distribution system. Conclusions This case is the first reported PAM death associated with culturable N. fowleri in tap water from a U.S. treated drinking water system. This case occurred in the context of an expanding geographic range for PAM beyond southern tier states with recent case reports from Minnesota, Kansas, and Indiana. This case also highlights the role of adequate disinfection throughout drinking water distribution systems and the importance of maintaining vigilance when operating drinking water systems using source waters with elevated temperatures.

Proteus syndrome (PS) is characterized by progressive, disproportionate, segmental overgrowth and tumor susceptibility caused by a somatic mosaic AKT1 activating mutation. Each individual has unique manifestations making this disorder extremely heterogeneous. We correlated three variables in 38 tissue samples from a patient who died with PS: the gross affection status, the microscopic affection status, and the mutation level. The AKT1 mutation was measured using a PCR-based RFLP assay. Thirteen samples were grossly normal; six had detectable mutation (2-29%) although four of these six were histopathologically normal. Of the seven grossly normal samples that had no mutation, only four were histologically normal. The mutation level in the grossly abnormal samples was 3-35% and all but the right and left kidneys, skull, and left knee bone, with mutation levels of 19%, 15%, 26%, and 17% respectively, had abnormal histopathology. The highest mutation level was in a toe bone sample while the lowest levels were in the soft tissue surrounding that toe, and an omental fat nodule. We also show here that PS overgrowth can be caused by cellular proliferation or by extracellular matrix expansion. Additionally, papillary thyroid carcinoma was identified, a tumor not previously associated with PS. We conclude that gross pathology and histopathology correlate poorly with mutation levels in PS, that overgrowth can be mediated by cellular proliferation or extracellular matrix expansion, and that papillary thyroid carcinoma is part of the tumor susceptibility of PS. New methods need to be developed to facilitate genotype-phenotype correlation in mosaic disorders.

Acute promyelocytic leukemia (APL) accounts for 5-8% of acute myeloid leukemias (AMLs). Myeloid sarcomas (MS) are rare extramedullary tumors consisting of immature myeloid cells. These tumors may develop de novo or concurrently with AML and may precede or coincide with the occurrence of AML. The occurrence of MS in an APL patient is a rare clinical event. In these cases, it usually occurs as a sign of relapse. Focal bone marrow involvement by APL is also rare; the majority of cases of APL demonstrate a diffusely hypercellular bone marrow throughout the axial skeleton due to expansion of neoplastic blasts/promyelocytes. We describe a 23-year-old female who presented with gait problems, including multiple falling episodes, and lower extremity weakness. An MRI demonstrated a paraspinal soft tissue mass. Histopathologic analysis demonstrated a myeloid sarcoma expressing CD45, myeloperoxidase, CD117, BCL2, focal weak CD34, and weak CD99 and negative for CD30, TdT, CD20, CD3, and CD10. The bone marrow aspirate demonstrated blasts/promyelocytes accounting for approximately 26% of the total bone marrow aspirate cellularity. The bone m a r r o w b i o p s y a n d c l o t s e c t i o n d e m o n s t r a t e d normocellularity with a few blast/promyelocyte foci on the clot section accounting for approximately 5% of total bone marrow cellularity. These foci expressed MPO and CD117 and were negative for CD34. Flow cytometry demonstrated blasts accounting for approximately 31% of all CD45+ events expressing MPO,

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Background: Although squamous cell carcinoma accounts for >90% of all oropharyngeal neoplasms, other rare neoplasms have been reported. Here, we present a case of mucoepidermoid carcinoma of the lingual tonsil. Methods and results:A 66-year-old male presented with a right neck mass and right base of tongue fullness. Fine needle aspiration of the neck mass and surgical biopsy of the base of tongue lesion revealed a low-grade mucoepidermoid carcinoma, ultimately staged as a T4N2aM0 neoplasm. Our multi-disciplinary tumor board recommended a right mandibulotomy, partial glossectomy, radical tonsillectomy, lateral pharyngeal wall resection, selective neck dissection levels II-IV, and reconstruction with an anterior lateral thigh flap followed by adjuvant radiation. Conclusion: Mucoepidermoid Carcinoma is the most common malignant salivary gland neoplasm; however, mucoepidermoid carcinoma arising from minor salivary rests within the lingual tonsils is exceedingly rare, presenting a diagnostic and therapeutic dilemma.