Disorders with primary and secondary deposition in the skin

ICD-11

5D00.Z

Synonyms

Amyloidosis, Mucinosis, Myxoedema, Hyalinosis, Xanthoma/Xanthelasma, Gout/Hyperuricaemia, Calciphylaxis, Tattoo.

Epidemiology

These are rare diseases. AL amyloidosis occurs in about 3–13 per million people per year.

Definition

Disorders with primary and secondary deposition in the skin are a heterogenous group of diseases, characterized by the pathological accumulation of materials in the extracellular matrix of the dermis or subcutis.

Aetiology & Pathogenesis

Primary localized cutaneous amyloidosis: idiopathic or mutations in the OSMR or IL31RA gene.

Secondary (AL) amyloidosis: light chain deposits that are produced by malignant plasma cells.

Mucinosis: thyroid disorders (myxoedema), lymphomas, inflammatory skin diseases.

Uric acid deposits (gout): idiopathic or linked to food excess.

Calciphylaxis: terminal chronic renal deficiency.

Skin calcinosis: connective tissue diseases.

Tattoos: trauma, voluntary intradermal pigment injection or deposition of dust and burnt substances.

Signs & Symptoms

Primary localized cutaneous amyloidosis: severely itchy patches of thickened, scaly and reddish-brown skin with multiple small bumps (lichen amyloidosis) or flat and dark brown patches (macular amyloidosis).

Secondary (AL) amyloidosis – vessel fragility with pinch purpura and periorbital purpura, unexplained bleeding or macroglossia.

Mucinosis – flat, shiny erythematous plaques.

Myxoedema – skin coloured flexible plaques, “orange peel” surface, pretibial location frequently, rarely hyperkeratosis.

Xanthoma/xanthelasma – small yellowish soft nodules, grouped.

Connective tissue disorders-associated calcinosis – rock hard subcutaneous nodules that may fistulate.

Calciphylaxis – skin necrosis with accompanying erythematous network like maculae (livedo), extremely painful.

Pathological tattoos – black, grey or brown macules of millimetric size, localized.

Localisation

Primary localized cutaneous amyloidosis – lichen amyloidosis: extensor faces of the limbs, and macular amyloidosis: often interscapular.

Secondary (AL) amyloidosis – periorbital or at skin sites exposed to wear and tear/physical trauma.

Mucinosis – depends on the etiology.

Myxoedema – frequently pre-tibial.

Xanthelasma – peri-orbital.

Xanthoma – frequently over pressure points.

Calciphylaxis – fatty areas of the body (abdomen, flanks, buttocks, thighs, breasts in women).

Tattoos – anywhere.

Gout – hallux (also called podagra) or fingers (also called tophus).

Laboratory & other workups

Secondary amyloidosis – blood count, serum electrophoresis and immunofixation, kappa/lambda light chain measurement in blood, eventually bone marrow aspiration.

Myxoedema – thyroid hormones.

Xanthoma/xanthelasma – lipid profile.

Calciphylaxis – calcium, albumin, blood count, renal function.

Dermatopathology

Amyloidosis: congo red stain shows a green birefringence.

Gout: crystal depositions.

Xanthoma and xanthelasma: lipid deposits.

Mucinosis and myxoedema: mucopolysaccharides.

Course

Slow progression followed by a stabilisation. The treatment remains difficult in most depositional skin disorders.

Complications

These diseases may progress if the underlying disease is not treated.

Diagnosis

Clinical and histological.

Differential diagnosis

Other forms of depositional disorders.

Prevention & Therapy

Treatment of the underlying disease.

8.13 Disorders with primary and secondary deposition in the skin