• SLE → IgG, IgM, IgA deposits at BMZ + superficial lamina propria
• Lichen Planus (Erosive/Atrophic) → Autoimmune T-cell; BMZ involvement
• Cicatricial Pemphigoid → Subepidermal blistering from anti-BMZ antibodies

Intraepithelial Bulla

• Location: Within the epithelium

• Associated Conditions:

  • Herpes simplex

  • Herpes zoster

  • Chicken pox

  • Pemphigus

  • Hailey-Hailey disease (Familial benign pemphigus)

  • Epidermolysis bullosa (dystrophic recessive form)

  • Oral lesions of erythema multiforme

 Subepithelial Bulla

• Location: Below the epithelium

• Associated Conditions:

  • Pemphigoid

  • Bullous pemphigoid (most common subepithelial blistering disease)

  • Bullous lichen planus

  • Dermatitis herpetiformis

  • Epidermolysis bullosa

  • Skin lesions of erythema multiforme

Non-epithelial cysts (not true cysts)

Solitary bone cyst

Radiology

The solitary bone cyst appears as a well-defined but non-corticated radiolucency. Typically, it has little effect
on adjacent structures and 'arches' up between the roots of teeth .

The inferior dental canal may not be displaced, but the cortical margins of the canal may be lost where it overlies the lesion. Expansion is rare.

Pathology

The cyst is lined by fibrovascular tissue that often includes haemosiderin and multinucleate giant cells.

Aneurysmal bone cyst

Radiology

The aneurysmal bone cyst typically presents as a fairly well-defined radiolucency. Sometimes it has a multilocular appearance because of the occurrence of internal bony septa and opacification. Marked expansion is a feature.

Pathology

The predominant feature of an aneurysmal bone cyst is the presence of blood-filled spaces of variable size lying in a stroma rich in fibroblasts, multinucleate giant cells and haemosiderin. Deposits of osteoid are also seen
 

• Actinomycosis (Sulfur Granules):

  • Yellow sulfur granules: Are actually bacterial colonies.

  • Histopathology: Colonies appear "cotton wool" shaped. (Note: "Cotton wool appearance" is seen radiographically in Paget's disease).

• Tuberculosis (TB):

  • Diagnosis (Gold Standard): Presence of acid-fast bacilli in sputum.

  • Staining Method: Ziehl-Neelsen staining method is used to identify acid-fast bacilli.

  • Scrofula: TB of cervical lymph nodes.

  • Lupus Vulgaris: TB of skin.

• Tongue & Gingival Appearance in Systemic Conditions:

  • Strawberry tongue and Raspberry tongue: Seen in stomatitis of Scarlet Fever.

  • Strawberry Gingivitis: Seen in Wegener's Granulomatosis.

• Lichen Planus:

  • Reticular form: Most common type, characterized by Wickham's striae.

  • Malignant potential: Atrophic and erosive forms are associated with significant malignant transformation risk.

  • Histology: Saw-tooth shaped rete pegs.

• Solar Elastosis: Characterized clinically by "sailor's skin" or "farmer's skin" (due to chronic sun exposure).

• Psoriasis & Hereditary Gingival Fibromatosis: Both show test tube-shaped rete pegs histologically.

• LE Cell Test: LE cells represent rosettes of neutrophils that have phagocytosed other leukocytes (seen in Systemic Lupus Erythematosus).

• Tzanck Cells: Seen in vesiculobullous conditions like Pemphigus, Herpes Simplex, Varicella, Herpes Zoster, and CMV infection.

• Ectodermal Dysplasia: Characterized by truncated, conical teeth and missing teeth (hypodontia).

• Widened Periodontal Ligament Space: Extreme widening seen in Scleroderma and Osteosarcoma.

• Geographic Tongue & Psoriasis: Share a common histological feature: Munro's abscesses (neutrophilic microabscesses).

• Schilling Test: Done to identify the deficiency of either extrinsic (dietary vitamin B12) or intrinsic factor involved in Pernicious Anemia.

• Fanconi's Syndrome: Associated with Aplastic Anemia.

• "Safety-Pin" Cells: Characteristic finding in Thalassemia / Erythroblastic Anemia.

• Radiographic Features of Anemias:

  • "Salt and Pepper" effect (Intraoral Periapical Radiograph): Found in Cooley's Anemia (Thalassemia) and Sickle Cell Anemia.

  • "Hair-on-End" pattern (Skull Radiograph): Found in Thalassemia, Sickle Cell Anemia, Congenital Hemolytic Jaundice, Chronic Iron Deficiency Anemia.

• "Rh Hump" (Erythroblastosis Fetalis): Describes a ring-like defect.

• Plummer-Vinson Syndrome: Associated with Iron Deficiency Anemia.

• Chediak-Higashi Syndrome: Giant abnormal PAS positive granules found in peripheral circulating leukocytes are basically altered lysosomes.

• Philadelphia Chromosome: Translocation of chromosomal material from chromosome 22 to chromosome 9; found in Chronic Myeloid Leukemia (CML).