The Dermatopathologist Quiz - What Are These Lesions?

The education series for dermatologists is presented by the Weill Cornell Comprehensive Dermatopathology Service.

Case 1. A 16-year-old female with bilateral medial thigh lesions (Figures A-G).

A. Mycosis fungoides

B. Pityriasis rosea

C. Pityriasis lichenoides chronica

D. Secondary syphilis

Case 2. 

A 40-year old woman presented with a knee lesion (Figures A-E).

A. Pilar leiomyoma

B. Myofibroma

C. Neurofibroma

D. Dermatofibroma

Case 3. 

A 32-year-old man presented with a right nostril mass (Figures A-E).

A. Basal cell carcinoma

B. Squamous cell carcinoma

C. Desmoplastic trichilemmoma

D. Clear cell hidradenoma

Case 1 Answer

 C. Pityriasis lichenoides chronica

The pattern is typical for pityriasis lichenoides chronica including the thick ichthyotic-like parakeratotic scale, pattern of psoriasiform epidermal hyperplasia, unusual tropism of lymphocytes and histiocytes through the more superficial layers of the epidermis accompanied by a superficial lymphocytic purpuric vascular reaction with overall mild lymphoid atypia. Mycosis fungoides can develop in a background of pityriasis lichenoides; however, the lymphoid atypia is insufficient to warrant categorization as mycosis fungoides.

Case 2 Answer

 A. Pilar leiomyoma

Pilar leiomyomas are benign circumscribed tumors composed of intersecting fascicles and bundles of smooth muscle. Tumor nuclei are elongated and blunt-ended or "boxcar" shaped. The cytoplasm is eosinophilic. Mitoses are scarce or absent.

Case 3 Answer  

C. Desmoplastic trichilemmoma

Trichilemmomas typically present as solitary lesions on the face but when multiple can be associated with Cowden syndrome. The typical histologic features as seen in this case are: overall circumscription, endophytic growth, peripheral palisading, one or more connections to the epidermis, thickened basement membranes, glycogenated cuboidal cells with clear cytoplasm and round nuclei, squamous whorls and keratinization.

Dr Magro is the director of dermatopathogy at Well Cornell Medicine in New York, NY. For more information, please visit www.weillcornelldermpath.com

Disclosure: The author reports no relevant financial relationships.

The education series for dermatologists is presented by the Weill Cornell Comprehensive Dermatopathology Service.

Case 1. A 16-year-old female with bilateral medial thigh lesions (Figures A-G).

A. Mycosis fungoides

B. Pityriasis rosea

C. Pityriasis lichenoides chronica

D. Secondary syphilis

Case 2. 

A 40-year old woman presented with a knee lesion (Figures A-E).

A. Pilar leiomyoma

B. Myofibroma

C. Neurofibroma

D. Dermatofibroma

Case 3. 

A 32-year-old man presented with a right nostril mass (Figures A-E).

A. Basal cell carcinoma

B. Squamous cell carcinoma

C. Desmoplastic trichilemmoma

D. Clear cell hidradenoma

The education series for dermatologists is presented by the Weill Cornell Comprehensive Dermatopathology Service.

Case 1. A 16-year-old female with bilateral medial thigh lesions (Figures A-G).

A. Mycosis fungoides

B. Pityriasis rosea

C. Pityriasis lichenoides chronica

D. Secondary syphilis

Case 2. 

A 40-year old woman presented with a knee lesion (Figures A-E).

A. Pilar leiomyoma

B. Myofibroma

C. Neurofibroma

D. Dermatofibroma

Case 3. 

A 32-year-old man presented with a right nostril mass (Figures A-E).

A. Basal cell carcinoma

B. Squamous cell carcinoma

C. Desmoplastic trichilemmoma

D. Clear cell hidradenoma

Case 1 Answer

 C. Pityriasis lichenoides chronica

The pattern is typical for pityriasis lichenoides chronica including the thick ichthyotic-like parakeratotic scale, pattern of psoriasiform epidermal hyperplasia, unusual tropism of lymphocytes and histiocytes through the more superficial layers of the epidermis accompanied by a superficial lymphocytic purpuric vascular reaction with overall mild lymphoid atypia. Mycosis fungoides can develop in a background of pityriasis lichenoides; however, the lymphoid atypia is insufficient to warrant categorization as mycosis fungoides.

Case 2 Answer

 A. Pilar leiomyoma

Pilar leiomyomas are benign circumscribed tumors composed of intersecting fascicles and bundles of smooth muscle. Tumor nuclei are elongated and blunt-ended or "boxcar" shaped. The cytoplasm is eosinophilic. Mitoses are scarce or absent.

Case 3 Answer  

C. Desmoplastic trichilemmoma

Trichilemmomas typically present as solitary lesions on the face but when multiple can be associated with Cowden syndrome. The typical histologic features as seen in this case are: overall circumscription, endophytic growth, peripheral palisading, one or more connections to the epidermis, thickened basement membranes, glycogenated cuboidal cells with clear cytoplasm and round nuclei, squamous whorls and keratinization.

Dr Magro is the director of dermatopathogy at Well Cornell Medicine in New York, NY. For more information, please visit www.weillcornelldermpath.com

Disclosure: The author reports no relevant financial relationships.

Case 1 Answer

 C. Pityriasis lichenoides chronica

The pattern is typical for pityriasis lichenoides chronica including the thick ichthyotic-like parakeratotic scale, pattern of psoriasiform epidermal hyperplasia, unusual tropism of lymphocytes and histiocytes through the more superficial layers of the epidermis accompanied by a superficial lymphocytic purpuric vascular reaction with overall mild lymphoid atypia. Mycosis fungoides can develop in a background of pityriasis lichenoides; however, the lymphoid atypia is insufficient to warrant categorization as mycosis fungoides.

Case 2 Answer

 A. Pilar leiomyoma

Pilar leiomyomas are benign circumscribed tumors composed of intersecting fascicles and bundles of smooth muscle. Tumor nuclei are elongated and blunt-ended or "boxcar" shaped. The cytoplasm is eosinophilic. Mitoses are scarce or absent.

Case 3 Answer  

C. Desmoplastic trichilemmoma

Trichilemmomas typically present as solitary lesions on the face but when multiple can be associated with Cowden syndrome. The typical histologic features as seen in this case are: overall circumscription, endophytic growth, peripheral palisading, one or more connections to the epidermis, thickened basement membranes, glycogenated cuboidal cells with clear cytoplasm and round nuclei, squamous whorls and keratinization.

Dr Magro is the director of dermatopathogy at Well Cornell Medicine in New York, NY. For more information, please visit www.weillcornelldermpath.com

Disclosure: The author reports no relevant financial relationships.