From Endometriosis to Lipedema: Toward a Neuroimmune Framework for Pain Amplification in Hormone-Sensitive Disorders

Background: Endometriosis and lipedema are chronic female-predominant disorders characterized by persistent pain that is frequently disproportionate to anatomical lesion burden. Although traditionally interpreted within distinct lesion-centered frameworks, both conditions exhibit striking clinical and epidemiological parallels, including hormonally modulated symptom dynamics, overlap with central pain syndromes, weak correlation between structural disease severity and pain intensity, and symptom clustering during reproductive transitions such as puberty, pregnancy, and menopause. Methods: This study aims to synthesize clinical, molecular, neuroimmune, and endocrine evidence on the interrelationship between endometriosis and lipedema, and to propose a hypothesis-generating neuroimmune framework linking both conditions. This integrative narrative review conducted a non-systematic literature search in PubMed/MEDLINE, Scopus, and Web of Science, focusing on mechanisms related to chronic pain, mast cell biology, TRPV1 signaling, CGRP-mediated neurogenic inflammation, intracrine steroidogenesis, and peripheral and central sensitization. Results: The review identifies convergent biological characteristics between the two diseases, including mast cell activation, macrophage polarization, endothelial dysfunction, fibrosis, angiogenesis, intracrine estrogen metabolism, and persistent inflammatory signaling. In endometriosis, direct evidence demonstrates increased sensory innervation, nerve growth factor expression, TRPV1 sensitization, CGRP-positive fibers, and mast cell-nerve interactions. In lipedema, convergent upstream mechanisms, including mast cell infiltration, elevated histamine levels, adipose tissue inflammation, and local estrogen activation, support the plausibility of a functionally analogous neuroimmune organization, despite incomplete direct neural characterization. In this context, the mast cell-TRPV1-CGRP axis is proposed as a biologically plausible framework, directly supported in endometriosis and currently hypothetical in lipedema, connecting peripheral sensitization, neurogenic inflammation, hormonal chronodependence, and central nociceptive amplification. The model further conceptualizes pain crises as transient events of instability within a sensitized neuroimmune network and proposes mechanistic phenotypes that integrate gastrointestinal, inflammatory, central, and hormonal triggers. Conclusion: Endometriosis and lipedema may represent topographically distinct manifestations of a shared neuroimmune process operating within hormone-sensitive tissues. Although the evidentiary basis remains asymmetric, with stronger mechanistic support in endometriosis than in lipedema, this framework provides a biologically plausible and experimentally testable model integrating endocrine, immune, neural, and vascular contributors to chronic pain amplification. This perspective supports coordinated translational investigation across reproductive biology, endocrinology, and pain medicine and may contribute to future mechanism-based stratification and therapeutic development. This work is hypothesis-generating and is not intended to establish causality or to provide clinical recommendations; all proposed mechanistic and therapeutic inferences require prospective experimental validation.