Lymphatics

Background: Lipedema is a progressive adipofascial disorder marked by painful nodular fat deposition that is often mistaken for obesity. While tumescent liposuction reduces limb volume with relative lymphatic safety, persistent large, painful lobules frequently remain, and excisional strategies risk iatrogenic lymphatic injury. We evaluated the application of intraoperative indocyanine green (ICG) lymphography to identify and preserve lymphatic channels during debulking surgery for symptomatic lipedema. Methods: We conducted a single-center case series (University of Pittsburgh Medical Center, July 2023–December 2024) of adults with lipedema refractory to conservative therapy who underwent a selective dermato-lipectomy (lobule/skin excision) with or without tumescent liposuction. Patients with clinical lymphedema or dermal backflow in ICG were excluded. Near-infrared ICG (SPY-PHI) was used for pre-incision mapping and real-time intraoperative guidance; lymphatic trajectories were marked and spared during lobule excision. Primary measures included dermal backflow patterns and lymph node transit time; secondary outcomes were complications and symptom burden (Lymphedema Life Impact Scale, LLIS) through ≥24 months. Results: Eight patients (five female/three male; mean age 49.5 ± 14.4 years; median BMI 52.65 kg/m²) underwent ICG-guided surgery. Preoperatively, linear lymphatic patterns were visualized up to the knee in all patients, but dermal backflow patterns could not be visualized in 83% from the level of the knee to the groin. Still, 67% demonstrated inguinal nodal uptake (mean transit 24 min), suggesting preserved lymphatic transport. All cases achieved intraoperative confirmation of intact lymphatic flow after debulking. The mean liposuction aspirate was 925 ± 250 mL per lower extremity; the mean excision mass was 2209 ± 757 g per lower extremity. Complications included two superficial cellulitis events (25%) and one wound dehiscence (12.5%); no hematomas or skin necrosis occurred. No patient developed clinical or imaging evidence of iatrogenic lymphedema during follow-up. Conclusions: Intraoperative ICG lymphography is a practical adjunct for lymphatic-sparing debulking of symptomatic lipedema, enabling real-time identification and preservation of superficial collectors while addressing focal lobules. This hybrid approach—targeted tumescent liposuction followed by ICG-guided superficial dermato-lipectomy—was associated with meaningful symptom improvement and a low morbidity in this early series.

Indolent lymphoproliferative diseases or disorders (LPDs) derived from T cells or Natural Killer (NK) cells may be neoplastic or non-neoplastic, which are often difficult to distinguish from each other and from their aggressive counterparts. The etiology and pathogenesis are mostly nebulous and may be related to infections or immune dysfunction. Indolent lymphomas differ from the high-grade aggressive counterparts by a prolonged clinical course of persistent or relapsing disease, histology, immunophenotype, and genetics. In recent decades, indolent lymphomas or LPD of T or NK cell derivation have been increasingly recognized, causing diagnostic and nosologic confusion. The issue is particularly challenging in the arena of indolent intestinal lymphomas and LPD, as evidenced by the myriad of names given to the indolent intestinal T- and NK-cell lymphomas and LPD. Confounding the picture are also reports of Epstein–Barr virus (EBV) positivity in various indolent non-intestinal LPD and, rarely, even in indolent intestinal T-cell lymphoma, which have been widely accepted to be typically EBV-negative. This review aims to curate current information and understanding of these diseases with the goal of resolving these issues. The recently described indolent T-lymphoblastic proliferation (iTLBP) and the re-classified indolent primary cutaneous CD4-positive small or medium T-cell LPDs and primary cutaneous acral CD8-positive T-cell LPDs also require greater awareness and recognition. It is important to diagnose these indolent entities in order to avoid over-treatment and unnecessary therapeutic intervention and to provide for accurate prognostic prediction and appropriate follow-up.

Reactive intralymphovascular immunoblastic proliferation (ILVIP) is a rare and diagnostically challenging entity that can closely mimic intravascular large B-cell lymphoma (IVLBCL). We report the comprehensive clinicopathologic features of two patients with B-cell lineage ILVIP identified in bowel resection specimens. Both patients presented with small bowel obstruction requiring surgical intervention, and one patient was initially erroneously diagnosed with IVLBCL. Neither patient had systemic findings suggestive of lymphoma, such as lymphadenopathy, hepatosplenomegaly, or B symptoms. Histologic evaluation demonstrated focal ILVIP composed of intermediate-to-large B-lineage immunoblasts positive for CD45, CD79a, and MUM1 with polytypic light-chain expression, and negative for CD20, PAX5, CD138, Epstein–Barr virus, and HHV8. The immunoblasts showed a high proliferation index (80–100%) in both cases. Recognition of ILVIP in specimens resected for bowel obstruction in otherwise healthy patients is essential to avoid misinterpretation as intravascular lymphoma and prevent unnecessary treatment.