Gastric Perineurioma: A Rare Entity with Molecular Analysis and Literature Review.

BACKGROUND: Perineuriomas of the gastrointestinal tract are benign neoplasms that commonly develop in the distal colon and are identified during screening colonoscopy; however, perineuriomas of the stomach are exceedingly rare and less frequently identified. Differentiating gastric perineuriomas from other more serious gastric neoplasms is critical to avoid unnecessarily aggressive treatments. Thus far, only six patients with gastric perineurioma have been described, and the molecular characterization of this entity is still lacking. CASE PRESENTATION: We report a 52-year-old woman who presented with abdominal pain and gastric acid reflux and was found to have a 1.5 cm subepithelial gastric neoplasm composed of bland spindle cells displacing the gastric glands with no cytologic atypia or mitotic activity, suggesting a benign spindle cell neoplasm. Immunohistochemical analysis showed reactivity for perineurial markers glucose transporter-1 and epithelial membrane antigen, consistent with benign gastric perineurioma. DNA extracted from the tissue was used for a capture-based target sequence enrichment panel followed by Illumina next-generation sequencing and targeted bioinformatic analysis for oncogenic alterations within defined disease-associated target regions. No sequence variants in the BRAF gene were identified. CONCLUSIONS: This rare case of gastric perineurioma helps solidify our understanding of how to discern various types of gastric neoplasms through traditional laboratory analysis alongside genetic sequencing approaches. Although extremely rare, gastric perineurioma should be kept in the differential diagnosis when assessing spindle cell gastric tumors to avoid unnecessary therapies, and physicians should understand the molecular characteristics of benign versus malignant tumors.

Atypical presentation of progressive disseminated histoplasmosis in a patient recently diagnosed with AIDS.

Opportunistic infections, including progressive disseminated histoplasmosis (PDH), may have variable and surprising presentations in patients with AIDS. This can be either a primary infection or reactivation of a latent infection. Latent infections may occur due to being unmasked by the immune reconstitution inflammatory syndrome after the initiation of combined antiretroviral therapy. PDH can be difficult to diagnose in patients with AIDS due to its variable presentation and many overlapping symptoms with other opportunistic infections. Serum and urine antigen testing are highly sensitive and typically used as the initial diagnostic test to workup suspected PDH. However, negative antigen and antibody tests do not rule out Histoplasmosis capsulatum infection and suspicion should remain high for PDH in the right clinical context. A definitive diagnosis may require biopsy-proven narrow-based budding yeast. We present an interesting patient with AIDS who presented with worsening cognitive decline and was ultimately diagnosed with PDH based on biopsy histopathology in the setting of negative antigen and antibody testing.