Multiple Giant Cutaneous Horns in a Renal Transplant Recipient.

Sir,

Cutaneous horn is a clinical description of a hyperproliferation of compact keratin in response to a wide range of underlying benign and malignant pathologic changes. Here, we present a renal transplant recipient with multiple giant cutaneous horns.

A 51-year-old gentleman, presented with multiple warty lesions over the body of 5 years duration. He was on prednisolone (10 mg) and azathioprine (125 mg) following renal transplantation 12 years back. He had a large nontender right inguinal lymph node and multiple small axillary lymph nodes. There were multiple cutaneous horns of varying sizes over the forehead, right external ear, arm, and back. Keratinous outgrowths were seen arising from flesh colored nodules in these areas. The compact keratinous masses formed curved structures over the ear and arm and conical structure measuring about 6.5 cm over the back [Figures 1 and 2]. There were multiple hyperpigmented keratotic papules and plaques seen all over the body. Large verrucous plaque with peripheral hyperpigmented borders were seen over shoulder region, neck, and dorsa of fingers. The histopathology of all the cutaneous horns revealed keratoacanthoma [Figures 3 and 4], the plaque over the shoulder region showed Bowen's disease. The verrucous lesion (neck) and the inguinal lymph node revealed poorly differentiated squamous cell carcinoma. He was initiated on chemotherapy (cisplatin, 5-fluorouracil) along with radiotherapy. He was lost to follow-up.

Figure 1

(a) Curved compact hyperkeratosis arising from flesh colored nodule over external ear, (b) flesh colored nodule over forehead with central hyperkeratotic plug

Figure 2

(a) Curved compact hyperkeratosis arising from flesh colored nodule over arm on a background of hyperpigmented stuck on papules, (b) conical compact hyperkeratosis arising from flesh colored nodule over back

Figure 3

(a) The typical crateriform architecture of keratoacanthoma with a peripheral collarette (H and E, ×200), (b) well differentiated eosinophilic to pale staining glassy abundant cytoplasm characteristic of keratoacanthoma (H and E, ×400)

Figure 4

(a) Keratin filled crater (H and E, ×50), (b) squamous cells with abundant glassy cytoplasm (H and E, ×100), (c and d) squamous cells with abundant glassy cytoplasm (H and E, ×200)

Cutaneous horns are hard, conical, dense hyperkeratotic protrusion and resemble the horn of an animal.[12] The height of a cutaneous horn should be 1΍ times its greatest diameter of the base.[2] The horn can be cylindrical, conical, pointed, corrugated transversely and longitudinally, or curved like a Ram's horn. They rarely grow beyond 1 cm. Giant cutaneous horns are extremely rare. The sites of predilection include chronically sun damaged skin of the face, ears, dorsa of hands in older individuals and very rarely, the penis. There can be underlying benign, premalignant, and malignant cutaneous diseases. Surrounding inflammation, infiltration, and tenderness of the base, wide base, low height to base ratio favor a malignant etiology. The conditions that can be seen at the base of a cutaneous horn have been shown in Table 1. Actinic keratoses have been reported as the most common horn base entity (37.4%) in a study of 230 horns.[3] In another study of 643 cutaneous horns, 61% had a benign base pathology, 23% had a premalignant, and 16% had a malignant base pathology.[4] Giant cutaneous horns have been reported over verruca vulgaris, burns scar, seborrheic keratosis, and squamous cell carcinoma.[5678]

Table 1

Underlying pathology that can be seen in a cutaneous horn

There is a greater risk of malignant and premalignant skin lesions such as actinic keratoses, Bowen's disease, keratoacanthomas, squamous cell carcinomas in renal transplant recipients. All these entities can form a cutaneous horn. The risk of malignant skin lesions in renal transplant recipients is related to the degree of immunosuppression. Multiple giant cutaneous horns and the simultaneous presence of keratoacanthoma, squamous cell carcinoma, and Bowen's disease in a renal transplant recipient, as seen in our patient is a rare association.

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