We report the case of an 84-year-old man with multiple squamous cell carcinomas located on his bald scalp, arising in association with underlying paraffinoma. Histologically, poorly differentiated, acantholytic squamous cell carcinomas were located above characteristic pseudocystic spaces. Carcinomas have been reported in association with penile and breast paraffinomas, but we are unaware of any reports of squamous cell carcinoma arising over a scalp paraffinoma.

Mineral oil has been injected into the body for various cosmetic purposes. Specifically, in the 1940s, mineral oil was injected into the scalp as a treatment for alopecia. Such treatments have resulted in scalp erythema and scaling or asymptomatic focal nodularity of the scalp; the lag time can be as long as 30 years.1,2 Computed tomographic scans and magnetic resonance imaging findings reveal nonspecific masses, occasionally with focal calcification.3 Biopsy is diagnostic, revealing circular, empty-appearing spaces of varying sizes in a fibrotic dermis, with focal inflammation and foreign-body giant cells.1 Spaces appear vacant as mineral oil dissolves in the solvents used during tissue processing and fixation.

An 84-year-old man presented with a 4-cm tumor on the parietal scalp and a 1.5-cm tumor on the anterior scalp. The patient had a remote history of a squamous cell carcinoma of the crown of the scalp, arising in an area of alopecia; according to the patient's medical history, this carcinoma was treated with localized radiation. The patient underwent wide surgical excision of both scalp lesions after frozen section evaluation. The surgeon reported that the deep dermal and subcutaneous portions of the scalp were “abnormal in quality” with calcification and increased resistance to the cutting blade.

Grossly, the parietal scalp mass measured 5 × 4.5 × 1.5 cm in aggregate (3 pieces). The largest piece measured 3.1 × 3.1 × 1 cm and had a central superficial ulceration. The cut surface of the tissue was firm and appeared yellow, tan, and pink. The frontal scalp lesion measured 2.5 × 1.5 × 0.6 cm and had an irregular protuberant growth on the superficial surface, with the cut surface revealing a white firm mass.

Histopathologic examination revealed similar findings in both scalp lesions. Acantholytic, keratinizing, but poorly differentiated squamous cell carcinomas were seen overlying pseudocystic spaces of varying sizes in an eosinophilic stroma (Figure). Both lesions were focally ulcerated. No evidence of vascular invasion was present, although focal perineural invasion was seen in the parietal scalp lesion. The pseudocystic spaces appeared empty. Some of the pseudocystic spaces were surrounded by a histiocytic, foreign-body giant cell reaction with areas of focal ossification. No birefringent polarizable foreign material was seen. Adjacent epidermis displayed basal layer atypia and mild solar elastosis of the papillary dermis. On retrospective interview, the patient reported having had mineral oil injected into his scalp in the 1940s as a treatment for alopecia.

Acantholytic, keratinizing, but poorly differentiated squamous cell carcinoma (A; hematoxylin-eosin, original magnification ×200) overlying pseudocystic spaces of varying sizes in an eosinophilic stroma (B; hematoxylin-eosin, original magnification ×100)

Acantholytic, keratinizing, but poorly differentiated squamous cell carcinoma (A; hematoxylin-eosin, original magnification ×200) overlying pseudocystic spaces of varying sizes in an eosinophilic stroma (B; hematoxylin-eosin, original magnification ×100)

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To our knowledge, this is the first case of squamous cell carcinomas located adjacent to an underlying scalp paraffinoma. We feel this is an important finding, as paraffinomas in other sites have been associated with carcinoma. Squamous cell carcinoma has been described arising 35 years after penile self-injection of mineral oil.4 There is also a report of carcinoma of the breast5,6 in association with paraffinoma. Furthermore, occupational exposure to mineral oils is a known risk factor for carcinomas, often of the scrotum7; additionally, topical mineral oil, and more specifically the polycyclic aromatic hydrocarbon component, is carcinogenic in animal models.8 In summary, it seems plausible that this patient's paraffinoma may have been a factor in the development of his squamous cell carcinomas.

Certainly the patient had other factors contributing to his multiple squamous cell carcinomas. Both sunlight and radiation may have induced or promoted his tumors. The patient was subjected to mineral oil injections as an experimental therapy to promote hair growth, but no hair growth was ever noted. As a result of his alopecia, the scalp may have had significant sun exposure, although the patient was in the habit of wearing a hairpiece. Tissue adjacent to the scalp carcinomas did show evidence of sun damage, with basal layer atypia and mild solar elastosis. He also had radiation treatment of a prior scalp tumor on the crown of the head, and the patient could not recall the extent of the radiation field. These factors, in addition to his paraffinoma, may have caused him to have multiple tumors.

Although injections of mineral oil into the scalp for treatment of baldness is no longer performed, patients continue to inject mineral oil into various sites, with penile augmentation being a current popular goal.9 Paraffinoma may not only coexist with carcinoma, but may also be a risk factor in the development of carcinoma, especially in the context of other risk factors, such as sun exposure. It is necessary for clinicians and pathologists to be aware of this entity for proper diagnosis and management.

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The authors have no relevant financial interest in the products or companies described in this article.

Author notes

Reprints: Scott W. Binder, MD, Department of Pathology, University of California, Los Angeles, 13-145E CHS, 10833 Le Conte Ave, Los Angeles, CA 90095 ([email protected])