Gastric Spindle Cell Neoplasms With Mast Cells - A Pitfall In Diagnosis Of Gastric Biopsies

Introduction/Objective

Undifferentiated sarcoma, previously known as malignant fibrous histiocytoma (MFH), is a very rare primary neoplasm of stomach. It usually arises from soft tissue of extremities with an incidence of 1- 2/100,000, typically presenting in the 5th-7th decades of life with a slight male predominance. We report a case of gastric undifferentiated sarcoma which was interpreted as gastrointestinal stromal tumor (GIST) on initial biopsy.

Methods/Case Report

A 84 year old female presented to the Danbury Hospital emergency department with hematemesis and melena. Upper gastrointestinal endoscopy revealed a pedunculated mass in the cardia of stomach with ulceration, followed by a computed tomographic scan of chest and abdomen revealing a 2.9 cm mass along the proximal lesser curvature of the stomach. An endoscopic biopsy revealed a spindle cell neoplasm with immunohistochemical staining for c-kit consistent with GIST. She later underwent partial gastrectomy. Histopathology of the resected gastric tumor showed tumor cells arranged in sheets and storiform pattern, exhibiting spindled to polygonal morphology with marked nuclear pleomorphism, high mitotic activity (20 mitoses per 10 high power fields) and Touton type giant cells. Immunohistochemical stains demonstrated absence of staining for c-kit, DOG-1, CD34, actin, desmin, S100, cytokeratin AE1/AE3, CD3, CD5, CD20, CD21, CD15, CD30, ALK1, myeloperoxidase, CD1a and LCA. Numerous mast cells within the tumor stained for c-kit. Molecular testing for c-kit and PDGFRA mutations were negative. A final diagnosis of undifferentiated sarcoma with features of myxofibrosarcoma was rendered.

Results (if a Case Study enter NA)

NA.

Conclusion

Undifferentiated sarcomas are high grade malignant mesenchymal neoplasms without clear cellular differentiation or immunohistochemical marker. Only 4% of the total cases of undifferentiated sarcoma have been reported to be arising primarily from the gastrointestinal tract. They carry a poor prognosis with a 5 year survival of 47%. The main pitfall in our case was the positive uptake of c-kit stain by mast cells which led to the diagnosis of GIST in first gastric biopsy. We want to stress the importance of entertaining this diagnosis in the differential when encountered with a malignant gastric spindle cell neoplasm along with careful interpretation of c-kit stains in small biopsy specimens as the treatment and prognosis differs greatly from GIST.

Temperature-based phenology model for predicting the present and future establishment and distribution of recently invasive Spodoptera frugiperda (J. E. Smith) in India

Fall armyworm, Spodoptera frugiperda (J. E. Smith) is a polyphagous and highly destructive invasive insect pest of many crops. It was recently introduced into India and widely reported in almost all parts of India. Development of a temperature-based phenology model for predicting its rate of development and distribution will help in understanding the establishment and further spread of introduced invasive insect pests. Development, survival and reproduction parameters of S. frugiperda at six constant temperature conditions (15, 20, 25, 27, 30 and 35°C) were investigated and further validated with data generated under fluctuating temperature conditions. The estimated lower developmental threshold temperatures were 12.1°C for eggs, 11°C for larvae, 12.2°C for pupae, 15.13°C for males and 12.66°C for females. Degree-day (DD) requirements for the development of the different stages of S. frugiperda were 50, 250 and 200 DD for egg, larva and pupa, respectively. The best-fitted functions were compiled for each life stage to yield a phenology model, which was stochastically simulated to estimate the life table parameters. The developed phenology model predicted temperature ranges between 27 and 30°C as favourable for S. frugiperda development, survival and reproduction. The results revealed that maximum net reproductive rate (215.66 females/female/generation) and total fecundity (981.08 individuals/female/generation) were attained at 30°C constant temperature. The mean length of generations decreased from 74.29 days at 15°C to 38.74 days at 30°C. The maximum intrinsic rate of increase (0.138 females/female/day) and shortest doubling time (4.9 days) were also observed at 30°C. Results of simulated life table parameters showed high temperature-dependent development of S. frugiperda and complete development within all the tested constant temperature ranges (15-35°C). Simulated life table parameters for predicting risk indices of S. frugiperda in India indicated a significant increase in activity indices and establishment risk indices with a higher number of generations during future (2050 and 2070) climatic change scenarios compared to present conditions. Our results indicate that India will be highly suitable for the establishment and survival of S. frugiperda in future time periods.

Integrin-Kindlin3 requirements for microglial motility in vivo are distinct from those for macrophages

Microglia play a critical role in the development and homeostasis of the CNS. While mobilization of microglia is critical for a number of pathologies, understanding of the mechanisms of their migration in vivo is limited and often based on similarities to macrophages. Kindlin3 deficiency as well as Kindlin3 mutations of integrin-binding sites abolish both integrin inside-out and outside-in signaling in microglia, thereby resulting in severe deficiencies in cell adhesion, polarization, and migration in vitro, which are similar to the defects observed in macrophages. In contrast, while Kindlin3 mutations impaired macrophage mobilization in vivo, they had no effect either on the population of microglia in the CNS during development or on mobilization of microglia and subsequent microgliosis in a model of multiple sclerosis. At the same time, acute microglial response to laser-induced injury was impaired by the lack of Kindlin3-integrin interactions. Based on 2-photon imaging of microglia in the brain, Kindlin3 is required for elongation of microglial processes toward the injury site and formation of phagosomes in response to brain injury. Thus, while Kindlin3 deficiency in human subjects is not expected to diminish the presence of microglia within CNS, it might delay the recovery process after injury, thereby exacerbating its complications.