Histopathology Atlas

EPIDERMAL TUMORS OR TUMOR-LIKE LESIONS

• Histology:

  • Skin

• Benign lesions/neoplasms:

  • Epidermal nevus

  • Keratopapilloma

  • Verruca plantaris

  • Keratoacanthoma

  • Clear cell acanthoma

  • Warty dyskeratoma

  • Seborrhoeic keratosis

  • Epidermal cyst

• Premalignant:

  • Actinic (solar) keratosis:

    • Atrophic form

    • Hyperplastic form

  • Intraepidermal squamous-cell carcinoma - in situ

• Malignant neoplasms:

  • Squamous cell carcinoma

  • Verrucous carcinoma

  • Basal cell carcinoma:

    • Nodular variant

    • Superficial variant

    • Fibroepithelioma (Pinkus' tumor)

• Other dermatoses:

  • Psoriasis

  • Molluscum contagiosum

ADNEXAL TUMORS

• Cysts:

  • Tricholemmal cyst

  • Pilonidal cyst

  • Steatocystoma

• Hair follicles:

  • Benign:

    • Trichilemmoma

    • Trichoepithelioma

    • Pilomatrixoma

    • Pilar tumor (proliferating trichilemmal cyst)

    • Trichofolliculoma 

  • Malignant:

    • Tricholemmal carcinoma

    • Pilomatrical carcinoma

• Sebaceous glands:

  • Benign:

    • Sebaceous adenoma

    • Sebaceous nevus

    • Sebaceoma

  • Malignant:

    • Sebaceous carcinoma

• Sweat gland derived:

  • Benign:

    • Syringocystadenoma papilliferum

    • Papillary hidradenoma

    • Eccrine mixed tumour

    • Eccrine spiradenoma

    • Poroma eccrinale

    • Acrospiroma

    • Eccrine cylindroma

    • Apocrine hidrocystoma

  • Malignant:

    • Apocrine carcinoma

    • Eccrine carcinoma

MELANOCYTIC TUMOR

• Nevi:

  • Junctional/ marginal melanocytic nevus

  • Compound nevus

  • Intradermal pigmented nevus

  • Verrucous intradermal melanocytic nevus

  • Congenital melanocytic nevus

  • Blue nevus

  • Halo nevus - Sutton

  • Spitz nevus

  • Dysplastic nevus

• Other melanocytic lesions:

  • De novo melanocytic dysplasia

  • Solar lentigo

• Melanoma:

  • Melanoma in situ - lentigo maligna

  • Lentigo maligna melanoma - LMM

  • Superficial spreading melanoma - SSM

  • Acral lentiginous melanoma - ALM

  • Nodular melanoma:

    • Epithelioid cell-type

    • Spindle cell-type

OTHER TUMORS OF SKIN

• Lymphoma:

  • Mycosis fungoides

  • Primary cutaneous T-cell lymphoma

  • Diffuse large B-cell lymphoma - DLBCL

• Neuroectodermal tumors:

  • Benign:

    • Schwannoma

    • Neurofibroma

    • Granular cell myoblastoma, Abrikosoff tumor

  • Malignant:

    • Merkel cell carcinoma

    • Malignant peripherial nerve sheath tumor - MPNST

• Vascular tumors:

  • Benign:

    • Pyogenic granuloma

    • Arteriovenous haemangioma

    • Cavernous haemangioma

    • Capillary hemangioma

    • Cavernous lymphangioma

    • Glomus tumor

  • Malignant:

    • Angiosarcoma

• Fibrohistiocytic tumors:

  • Benign:

    • Keloid

    • Hypertrophic cicatrix

    • Benign fibrous histiocytoma

    • Dermatofibroma

    • Langerhans cell histiocytosis

    • Juvenile xanthogranuloma

  • Malignant:

    • Dermatofibrosarcoma protuberans

• Adipocytic tumors:

  • Benign:

    • Lipoma

    • Hibernoma

  • Malignant:

    • Lipoblastoma

    • Liposarcoma

• Other lesions:

  • Cutaneous leiomyoma

  • Cutaneous leiomyosarcoma

  • Rheumatic nodules

  • Multinucleated foreign body giant cell granulomatous reaction

  • Cutaneous mastocytosis

  • Demodex