Metastasis of a basosquamous carcinoma arising in a nevus sebaceus

Nevus sebaceus (NS) is a congenital hamartoma of skin structures including the epidermis, sweat sebaceous glands, and hair follicles. It is known that secondary tumors can occur in NS. However, secondary metastatic malignancies are rare. Basosquamous carcinoma (BSC) is an aggressive type of basal cell carcinoma (BCC) characterized by squamous differentiation. Herein, we report a case of metastatic BSC that developed in a 73-year-old male with NS. The clinical presentation of this patient was that of an ulcerative nodule developing in a longstanding plaque-like lesion consistent with NS. Histopathological examination revealed characteristic features of BCC with some areas of squamous differentiation in addition to the structure of a typical NS. Immunohistochemical expression of Ber-EP4, AE1/AE3, and epithelial membrane antigen helped to make the diagnosis of BSC.

Detection by (18)F-FDG PET of unsuspected extensive bone marrow metastases in a case of basosquamous carcinoma of the cheek

Basosquamous carcinoma (BSC) is a rare type of malignancy with features of both basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) with a potential for aggressive behaviour infiltration and destruction. First reported by MacCormac in 1910 in a series of rodent ulcers, this entity does have an increased risk of recurrence and metastases as well, which distinguish it from other forms of basal cell carcinoma. The overall incidence of basosquamous carcinoma ranges from 1.2% to 2.7%. An unusual case of basosquamous carcinoma (BSC) is presented where 18- fluorodeoxyglucose positron emission tomography ((18)F-FDG-PET) scan diagnosed unsuspected extensive metastatic disease in the bone marrow, which was further proven histopathologically. The patient was a 32 years old man with history of recently diagnosed basosquamous carcinoma of left cheek involving left lower eyelid and left eyeball. Contrast enhanced computed tomography(ceCT) of the head and neck demonstrated involvement of the left cheek skin by the malignancy along with erosion of zygomatic bone and phthisis bulbi of the left eye. The serum alkaline phosphatase was elevated (255units, normal range 50-150units). The patient was referred for (18)F-FDG PET, for disease status evaluation. The scan showed intense tracer uptake in the left zygomatic region, the site of known primary disease. Intense tracer uptake was noted in the multiple lesions of bone marrow of axial as well as appendicular skeleton. The scan appearance was highly suggestive of metastatic bone marrow involvement. A bone marrow biopsy was performed to confirm the scan findings. Guided by the (18)F-FDG PET scan findings, bone marrow biopsy was performed and metastatic basosquamous carcinoma was diagnosed. We believe this is the first reported case of basosquamous carcinoma where extensive metastatic bone marrow disease was diagnosed with the aid of (18)F-FDG PET. At first diagnosis, an advanced stage of BSC is often present. Due to its metastatic potential, extensive primary surgical resection of BSC, possibly completed by radiation or photodynamic adjuvant treatment is recommended. Given the aggressive nature of basosquamous carcinoma, whole body (18)F-FDG PET is very useful in diagnosing metastatic BSC. In conclusion, this is the first reported case of the use of (18)F-FDG PET study for diagnosing metastatic bone marrow disease in a patient with basosquamous carcinoma.

Cancer of the skin of the nose

In 456 cases of cancer of the skin of the nose there was an even distribution in the sexes with the highest incidence occurring in the fifth and sixth decades. Basal cell cancer comprised 87%, occurring predominantly on the ala, tip and root; squamous cell cancer, more common on the lateral borders and columella, occurred in 10.7% of the cases. Previous exposure to irradiation was the most pernicious etiological factor. Fifty-one percent had been previously treated inadequately and presented with a recurrence. Metastases developed in 0.25% of the basal cell cancers and in 18.5% of the squamous cell cancers. Nine percent had recurrence after definitive treatment. Treatment was predominantly surgical excision, but irradiation, electrodesiccation and combinations of these with chemosurgery were also used. One patient with basal cell, five with squamous cell and one with sweat gland tumor died as a result of carcinoma of the skin of the nose. Another small group, previously exposed to full face irradiation, became chronic producers of recurrent cancer of the skin of the face (and nose); eight of these patients died as a result of cancer of the skin of the face.