Page 40 - Concise Pathology for Exam Preparation ( PDFDrive )

1 Cell Injury and Cell Death 25

Smooth muscle cells

Hyaline change

FIGURE 1.15. Hyaline degeneration in a leiomyoma (H&E; 2003).

Accumulation of Pigments
Pigment refers to material that has colour and can be seen without staining. In pathology,
pigments play an important role in the diagnosis of diseases such as gout, jaundice, mela-
nomas, albinism and haemorrhage. They can be classified as
1. Endogenous pigments
(a) Melanin:
(i) Nonhaemoglobin-derived brown-black pigment (Fig. 1.16)
(ii) Normally present in skin, hair, choroids, meninges and adrenal medulla
(iii) Synthesized by melanocytes and dendritic cells
Disorders of pigmentation involving melanin:
• Hyperpigmentation:
• Addison disease
• Adrenogenital syndrome
• Chloasma/melasma

Malignant cells

Melanin

FIGURE 1.16. Intracellular and extracellular melanin deposits in a malignant melanoma
(H&E; 4003).

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