Salivary duct carcinoma is a rare, aggressive salivary gland malignancy that morphologically and immunophenotypically resembles breast ductal carcinoma. The rhabdoid variant is characterized by discohesive tumor cells with rhabdoid cytomorphology, frequent loss of E-cadherin expression, and morphologic overlap with pleomorphic invasive lobular carcinoma of the breast. We report a 74-year-old man who presented with an enlarging right buccal mass and trismus. Positron emission tomography–computed tomography demonstrated right cervical lymphadenopathy with no evidence of breast or lung primary. Resection revealed a discohesive, infiltrative tumor composed of pleomorphic rhabdoid cells, with scattered cells containing intracytoplasmic mucin imparting a signet-ring morphology, and prominent targetoid perineural invasion. Immunohistochemically, the tumor showed diffuse positivity for keratin 7, gross cystic disease fluid protein 15 (GCDFP15/PIP), androgen receptor, weak GATA3 expression, loss of E-cadherin, and cytoplasmic p120-catenin (CTNND1) staining, a profile closely resembling that of invasive lobular carcinoma. Extensive nodal metastases were identified. Despite multimodal therapy, the disease recurred. This report highlights the importance of recognizing salivary duct carcinoma with rhabdoid features to avoid misdiagnosis and guide appropriate management.

Background and Clinical Significance: Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome characterized by excessive activation of the immune system. Case Presentation: We present the case of an eight-month-old infant with influenza A(H1N1) who presented with seizures, hepatosplenomegaly, cytopenias, and markedly elevated levels of ferritin, IL-18, and CXCL9, raising concern for HLH. Despite initiation of HLH-directed and antiviral therapy, she succumbed to cardiorespiratory failure. Genetic testing revealed heterozygous variants in LYST and NLRC4, suggesting a potential genetic predisposition. Conclusions: This case underscores the challenge of distinguishing primary from secondary HLH and highlights the importance of balancing aggressive immunosuppression with infection control. Early genetic and cytokine profiling may assist in guiding personalized treatment strategies, enabling targeted interventions that avoid excessive immunosuppressive treatment in cases of reactive hyperinflammation while facilitating timely escalation of therapy in true or refractory HLH.