Search

Small cell variant of medullary thyroid carcinoma is an extremely rare histologic entity with a paucity of data. As such, there is a lack of literature and clinical experience regarding this disease. In this report, we examine a case of small cell variant of medullary thyroid carcinoma that presented with intractable nausea, vomiting and diarrhea. While these symptoms were essentially refractory to the standard symptomatic treatment, further laboratory analysis revealed dramatically elevated calcitonin levels and mildly raised thyroid-stimulating hormone levels. Interestingly, repletion of thyroid hormone and treatment with lanreotide resulted in an abatement of our patient’s symptoms. This temporal clinical improvement highly suggests a potential role involving thyroid-stimulating hormone and calcitonin levels in the pathogenesis of this disease, and consequently suggests a role for thyroxine in treating the associated gastrointestinal symptoms.

Background Many gram-negative bacteria produce an outer membrane phospholipase A (PldA) that plays an important role in outer membrane function and is associated with virulence. Results In the current study, we characterized a pldA mutant of Coxiella burnetii, an intracellular gram-negative pathogen and the agent of human Q fever. The C. burnetti pldA open reading frame directs synthesis of a protein with conserved PldA active site residues. A C. burnetii ΔpldA deletion mutant had a significant growth defect in THP-1 macrophages, but not axenic medium, that was rescued by complementation. Thin layer chromatography was employed to assess whether pldA plays a role in remodeling membrane lipids during C. burnetii morphological differentiation. Extracted lipids were analyzed from replicating, logarithmic phase large cell variants (LCVs), non-replicating, stationary phase small cell variants (SCVs), and a mixture of LCVs and SCVs. Similar to Escherichia coli, all three forms contained cardiolipin (CL), phosphatidylglycerol (PG) and phosphatidylethanolamine (PE). However, PE and PG were present in lower quantities in the SCV while three additional lipid species were present in higher quantities. Co-migration with standards tentatively identified two of the three SCV-enriched lipids as lyso-phosphatidylethanolamine, a breakdown product of PE, and free fatty acids, which are generally toxic to bacteria. Developmental form lipid modifications required the activity of PldA. Conclusions Collectively, these results indicate developmentally-regulated lipid synthesis by C. burnetii contributes to colonization of macrophages and may contribute to the environmental stability and the distinct biological properties of the SCV. Electronic supplementary material The online version of this article (10.1186/s12866-018-1181-0) contains supplementary material, which is available to authorized users.

Anaplastic lymphoma kinase positive, anaplastic large cell lymphoma (ALCL) is an uncommon T-cell non-Hodgkin lymphoma. A rare morphological variant-small cell variant of ALCL may pose diagnostic challenge especially when it presents primarily as a soft tissue mass. We present a rare case of small cell variant of ALCL in a 14-year-old female presented with arm swelling with emphasis on clinical, morphological and immunohistochemical aspects. Pathologists should be aware of this entity when considering a differential diagnosis of malignant round cell tumor as early and correct diagnosis has important clinical implications.