Generalidades
- Tecido adiposo forma 10-20% do peso corporal normal
- Diferentes tipos de tecido adiposo
- Castanho - fetal
- Visceral
- Hipoderme
- Heterogenous group of disease affecting the subcutaneous fat (hipoderme)
- Constituido por
- Adipócitos - tem vacúolo
- Tecido conjuntivo
- Vasos e nervos
- Organizam-se
- Lobulos
- Septos
- Difficult topic due to:
- Clinica pouco variada (erythematous subcutaneous nodules on the lower extremities)
- Biopsia profunda, pernas onde não gostamos de fazer biópsia
- Achados histopatológicos são difíeis de interpretar
- Sobreposição morfológica
- Tempo de evolução da doença
- Furthermore, many of these disorders are not isolated to the subcutis, and may also affect the dermis and epidermis
- Processamento histológico diferente
- Biópsia deve ser elíptica e vai ser cortada longitudinalmente em vez de transversalmente como nos tumores
Classification
- Septal VS lobular
- Com ou sem vasculite
- Natureza do infiltrado
- Presença de depósitos, cristais
- Necrose dos adipócitos?
- Lipofágica
- Macrófagos espumosos
- Liquefação
- Celulas fantasma
- Por digestao enzimatica
- Hialinização
- Formação de material de hialina rodeando adipocitos mumificados
- Membranosa
- Microquistos
- Isquémica
- Palidez dos adipócitos
- Celulas fantasma pequenas
- Basofílica
- Important to realize these are not mutually exclusive… only “mostly” or “predominantly”
- No algorithm is perfect
Saurat
Septal
- Cura sem atrofia ou cicatriz (distingue das paniculites lobulares em que geralmente há atrofia ou cicatriz)
- Tem vasculite?
- Com vasculite - são vasculites
- Pequenos vasos - vasculite leucocitoclásica
- Médios vasos
- Artéria - poliarterite nodosa
- Veia - tromboflebite migratória superficial
- Sem vasculite
- Linfócitos e plasmócitos predominantes
- Histiócitos predominantes
Vasculitis
Leucocytoclastic Vasculitis
- Rarely presents as subcutaneous nodules and only deep
- Thickened septa with PMN’s, leukocytoclasis of SMALL blood vessels
Superficial Thromboflebitis
Polyarteritis Nodosa
Lymphocytic
Necrobiosis Lipoidica
Morphea/Scleroderma
- Can be entirely panniculitic!
- CAN BE EXCLUSIVE TO THE FAT
- Mainly lymphocytic without granulomas
- Thickened septa
- Spaces between collagen disappears
- DDx: eosinophilic fasciitis
Granulomatous
Subcutaneous Granuloma Annulare
- Can be entirely panniculitic!
- CAN BE EXCLUSIVE TO THE FAT
- Palisading granuloma around necrobiotic collagen and mucin
- May see nuclear dust, may see EOSINOPHILS
Rheumatoid nodule
- 20% of RA patients, poorer prognosis
- May be larger than other entities discussed
- Palisading granuloma around necrobiosis and FIBRIN
Necrobiotic Xanthogranuloma
- Yellowish, telangiectatic plaque
- Predilection for head/neck
- IgG kappa paraproteinemia
- Granulomatous, Touton-type giant cells
- Cholesterol clefts between collagen bundles
Erythema Nodosum
Lobular
Lobular: Vasculitis
Leprosy Treatment Reactions
- Erythema Nodosum Leprosum
- Th2
- Type III hypersensitivity
- Immune-mediated vasculitis of the fat lobules
- Tratamento
- TOC: thalidomide
- Alternatives: MTX or prednisone + clofazimine
- Lucio’s phenomenon
- Necrotizing vasculitis
- Dermal and fat vessels
- Ulcers
- Poor prognosis
- Thalidomide
Erythema Induratum
Metastatic Crohn’s Disease
- Difficult diagnosis
- Location is sometimes helpful (anogenital)
- Rare manifestation to have vasculitis in Crohn’s (Chron’s is usually granulomatous not vasculitic, but extraintestinal Crohn’s is the exception, may be vasculitic)
- On lower extremities, mimicks PAN and EN
- Both which can occur in conjuntion with Crohn’s
- Can be septal or lobular
- NON-caseating (distinguishes from EI)
Lobular: Paucicellular (non-vasculitic)
Sclerosing Panniculitis
- Lipodermatosclerosis
- Wood-like indurated plaques with telangiectasias, hyperpigmentation and edema in an inverted bottle shape of ankles
- Underlying chronic venous insufficiency
- Not evident on vascular studies
- Histologic
- Paucicellular, dermal fibrosis, and “lipomembranous” or “membranocystic” changes
- Cystic spaces with an eosinophilic corrugated membrane
- Necrose membrano quística
Calciphylaxis
Lobular: Lymphocytes
Cold Panniculitis
Lupus Panniculitis
- A type of CCLE (Chronic Cutaneous Lupus Erythematosus), rarely seen in SLE (Acute Lupus Erythematosus)
- Red, subcutaneous nodules which heal with atrophy
- If overlying & overt DLE, called “lupus profundus”
- Favorecem localizações atípicas para paniculite (membros superiores, face)
- Histology
- May see overlying changes of DLE
- Lobular, lymphocytic panniculitis with plasma cells
- “Lymphoid follicles” with plasma cells in periphery
- May see lymphocytic dust
- Densidade do infiltrado é tal que pode fazer DDx com linfoma
- Imunohistoquímica - identificação de agregados de celulas dendriticas plasmocitoides CD 123+
Lobular: Neutrophils
Pancreatic Panniculitis
- Associated with:
- Acute or chronic pancreatitis
- Also seen in acinar-cell type of pancreatic cancer
- Subcutaneous nodules ulcerate, extruding brownish, oily fluid (fat in the cell being degraded)
- Follows the course of pancreatitis (but not cancer)
- Arthritis → because of necrosis of periarticular fat tissue
- High lipase in most cases pathogenic
- However multifactorial because only 2-3% of pancreatitis patients have panniculitis, and panniculitis has been seen with normal lipase levels
- Histology
- Ghost adipocytes: coagulative necrosis of fat
- Saponification: proteolytic digestion of fat leads to dystrophic calcification
- Neutrophils in periphery
Alpha1 Antitrypsin Deficiency
- Only seen in the homozygous type (PiZZ)
- Emphysema, hepatitis, cirrhosis, vasculitis, angioedema and panniculitis
- Do not debride (precipitant)
- Histology: interstitial neutrophils in the lobules
Infective Panniculitis
Factitial Panniculitis
- Foreign body reaction
- Begins neutrophilic → granulomatous
- Iatrogenic
- Vitamin K, pentazocine, povidone
- Cosmetic
- Silicone or paraffin (mineral oil) → “swiss cheese”
- Psychiatric
- Urine, feces, milk, mustard, etc.
Lobular: Histiocytes
Subcutaneous Sarcoidosis
- Ver sarcoidose
- AKA Darier-Roussy subtype
- DDx is EN (but EN with more overlying erythema) - eritema nodoso é uma paniculite reativa no contexto de um doença subjacente (sarcoidose)
- Lobular not septal
- Histology
- Non-caseating granulomas in the fat lobules
- Pequenos granulomas característicos
Traumatic Panniculitis
- From blunt trauma
- Legs and breasts most commonly
- May be seen as a nodule post-surgically and mistaken for recurrence
- Histology
- Cystic spaces in the lobules of fat necrosis
- Anuclear adipocytes
- May see foamy histiocytes
Subcutaneous Fat Necrosis of Newborn
Sclerema Neonatorum
Subcutaneous Panniculitis-like T-cell Lymphoma
- More generalized, F>M
- Histology
- Atypical lymphocytes may form ring around adipocyte
- Cytophagosis by histiocytes (bean-bag cells)
- May be seen in bone marrow
- Up to 20% may develop hemophagocytic syndrome
- CD3+, CD8+, perforin, and TIA-1
Made with Bullet