Erythrocyte Ghosts and Plasma Beads as Antigen Peptide Delivery Systems in Animals and Humans

Note*: M: male, F: female, DOT: dorsum of the tongue, BLBOT: bilateral lateral borders of the tongue, BSL: benign symmetric lipomatosis, BLT: bilateral lipomatosis of the tongue, SLT: symmetric lipomatosis of the tongue.

The distinction between SLT and classic MSL remains unsettled. Some authors consider SLT a localized variant within the MSL spectrum; others argue for a distinct disease entity. Given the overlap in imaging and histology, SLT may represent a siterestricted form of symmetric lipomatosis.

A key component in establishing the diagnosis of symmetrical tongue lipomatosis lies in the radiologic characterization of the lesions. In soft-tissue tumors of fat origin, magnetic resonanc autonomic neuropathyures consistent with adipose tissue [24,25] On T1-weighted sequences, the lesions showed homogeneous high signal intensity comparable to subcutaneous fat. On fat-suppressed (or STIR/fat-sat) sequences, the signals were uniformly suppressed, confirming fatty composition. The absence of thick or irregular enhancing septa or nodular non-fatty components argues against well-differentiated liposarcoma or atypical lipomatous tumor, a distinction supported by prior imaging series demonstrating specificity of MRI for simple lipomas in well-defined fatty masses [26,27]. Moreover, the margins between the fatty lesions and the residual intrinsic tongue musculature were somewhat indistinct, consistent with a non-encapsulated or infiltrative pattern rather than a discrete encapsulated lipoma. This infiltrative or interdigitating appearance is characteristic of lipomatosis rather than isolated lipomas. In previous reports of symmetrical tongue lipomatosis, similar ill-defined margins and partial infiltration into muscle have been documented on MRI, supporting the notion of diffuse fatty overgrowth rather than mass-forming tumors [24,25].

Another discriminating point is the lack of enhancement after contrast administration: adipose tissue typically does not take up contrast, and any internal septa—if present—tend to be thin and nonenhancing. Thickened septa (>2 mm), nodular enhancing foci, or areas of non-fat signal raise suspicion for malignancy and should prompt further evaluation. In our imaging, no such suspicious features were apparent. Additionally, the bilateral, symmetric distribution in the same anatomical region (tongue margins) strengthens the diagnosis of a systemic or symmetric process rather than random isolated lipomas. Combined with the imaging features of mature fat signal, lack of aggressive MRI signs, and consistent symmetry, the radiologic evidence strongly supports a diagnosis of symmetrical lipomatosis of the tongue rather than differential diagnoses such as intramuscular lipoma, liposarcoma, or other infiltrative lesions.

The pathogenesis of symmetrical lipomatosis of the tongue remains uncertain, yet several plausible mechanisms have been proposed.

a) Mitochondrial dysfunction and altered lipid metabolism are considered the most compelling explanations. Studies of multiple symmetric lipomatosis have demonstrated mitochondrial DNA mutations leading to defective oxidative phosphorylation, impaired lipid degradation, and aberrant proliferation of brown adipose–like tissue. A similar mitochondrial defect could promote localized and bilaterally symmetric adipose accumulation within the tongue, where oxidative metabolism is physiologically active [5,28].

b) Autonomic dysregulation has also been implicated. Impaired adrenergic control of lipolysis may result in reduced fat breakdown and consequent deposition. Given the tongue’s dense sympathetic and parasympathetic innervation, focal disturbances in autonomic signaling could account for the remarkably symmetrical distribution of fatty tissue.

c) Alcohol-related or local metabolic factors may further contribute. Chronic ethanol exposure disrupts mitochondrial function, modifies adrenergic tone, and enhances lipogenesis while suppressing lipolysis. Even in the absence of overt alcohol abuse, subtle metabolic alterations or microvascular changes could trigger localized adipose proliferation [29,30].

Taken together, these observations suggest that symmetrical lipomatosis of the tongue may represent a localized phenotypic expression of systemic metabolic dysfunction, possibly driven by mitochondrial or autonomic impairment. The tongue’s unique muscular and vascular architecture may amplify such disturbances, resulting in the characteristic bilateral pattern. Further molecular and metabolic analyses are warranted to elucidate the precise mechanisms underlying this distinctive lesion. Clinically, differentiation from lipoma, lipomatosis of other origins, and infiltrative neoplasms such as well-differentiated liposarcoma is essential. MRI typically demonstrates diffuse, nonencapsulated, symmetrical fatty infiltration, which aids in distinguishing this condition from encapsulated lipomas. Histopathology remains the diagnostic gold standard. Treatment is primarily conservative, with surgical reduction indicated for functional or esthetic reasons. Recurrence is uncommon when complete excision is achieved, though residual fatty tissue may persist given the nonencapsulated nature of the lesion. Long-term follow-up is advised, as metabolic disturbances could predispose to further adipose proliferation. Therapeutically, symptomatic lesions are often resected [31,32]. However, complete excision may risk functional deficits, recurrence is possible, and many patients may benefit more from symptomatic and longitudinal management. In our case, surgical intervention was precluded by the patient’s overall condition - a limitation of this report.