Proliferating trichilemmal cyst

Fourteen eases (9 female, 5 male) of proliferating trichilemmal cysts are reported The patients age-range was 40–80, 12 being over 60. The cysts were present for 2–50 years and enlarged in the months or years before the observation. Seven were ulcerated. In 4 with multiple lesions both proliferating and ordinary trichilemmal cysts were present. The histological features were typical in all but one patient (evolution towards squamous cell carcinoma?) with some variation from lesion to lesion and from area to area in the same tumour. The microscopic features suggest that the proliferating trichilemmal cyst must be considered an hamartoma of the terminal hair follicle, not only related to the isthmic segment of the outer root sheath but with some differentiation (smaller and more variable) towards the infundibular and matricial segments. The tumour is likely to be a proliferating trichilemmal cyst from the beginning and not a peculiar evolution of an ordinary, pre-existant, trichilemmal cyst.     

Proliferating trichilemmal cysts over the vulva

A sixty-year-old woman with multiple proliferating trichilemmal cysts over the vulva is described. The appearance of the eruptions suggests a hamartomatous origin. The lesions in the later stages resembled basal cell carcinoma. The malignant potential of the cysts and their treatment are discussed.     

Proliferating trichilemmal cyst occurring on the shin

We report a patient who developed a proliferating trichilemmal cyst on his shin. Histological examination revealed the typical features of this lesion. Proliferating trichilemmal cysts characteristically occur on the scalp and occasionally on the upper trunk. We describe the first example of this uncommon condition on the leg.     

Proliferating trichilemmal cyst on the back.

A large intradermal tumor, 5times4 cm in size, developed on the back of 67-year-old Japanese woman. Histological examination revealed a large cyst next to a mass of irregular proliferation of the cystic wall, most of which showed typical trichilemmal keratinization. The accompanying partial calcification of the homogeneous cystic content allowed the diagnosis of proliferating trichilemmal cyst. Since this tumor is quite rare among the Japanese, the 15 cases so far reported in the Japanese literature are reviewed and summerized.     

Proliferating trichilemmal cyst: an ultrastructural study

A 73-year-old woman had a walnut-sized tumor in the occipital region for 10 years. The growth consisted of multiple small and large cystic epithelial masses. The cyst wall exhibited trichilemmal keratinization. Numerous squamous eddies as well as many glycogen-rich cells were present in the cyst wall. Some small round keratohyalin granules were observed in the cells below the horny layer. The desmosomes and masses of lipid droplets were seen in the horny layer. The findings described above are similar to those observed in the follicular isthmus and the follicular infundibulum. Other interesting findings include the presence of intranuclear inclusions of tonofilament-like material and/or keratohyalin-like granules within the cells near the mid-layer of the cyst wall.     

Proliferating trichilemmal cyst in an organoid nevus

An unusual tumor mass of the scalp found in an elderly woman is presented. This lesion had many features simulating a verrucous squamous cell carcinoma of the scalp. Pathologic findings eventually revealed the tumor mass to be a proliferating trichilemmal cyst. Differentiation between a benign and malignant process in these lesions can sometimes be difficult. Clinical as well as histopathologic evaluation is necessary to make an accurate diagnosis.     

Proliferating trichilemmal cyst with apocrine-acrosyringeal and sebaceous differentiation

An adnexal tumor on the scalp of a 74-year-old woman is described. Histologically, the tumor was composed of cystic structures showing typical trichilemmal keratinization. The tumor cells in the cyst walls often formed duct-like or squamous eddy-like structures and occasionally showed vacuolation or poroma-like change. Ultrastructurally, some tumor cells showed differentiation either toward the acrosyringium or sebaceous cells. From these findings, the present tumor is considered to differentiate toward various parts of the hair follicle including infundibulo-isthmus epithelium, apocrine acrosyringium, and sebaceous cells.     

Proliferating trichilemmal cyst with spindle cell carcinoma.

We report a 58-year-old woman with proliferating trichilemmal cyst (PTC), from which a spindle cell carcinoma arose. The tumor on her scalp had been removed at another hospital. Histological examination had revealed almost typical features of PTC. However, the case showed a partial transformation to spindle cell carcinoma, and transition zones between squamous epithelium and spindle cells were present. Three months after histologic examination, the patient came to us for the treatment of recurrent tumor. Despite surgical resection, the patient died as a result of distant metastases. Histologically, the recurrent tumor was composed of only spindle-shaped tumor cells. We describe the first example of this uncommon condition.     

Proliferating trichilemmal tumor of the nose

Proliferating trichilemmal tumor is a rare tumor originating in the external rootsheath, that is usually found in the scalp of middle-aged or elderly females. Itshistologic appearance may not correlate with its clinical behavior. In addition,there are no guidelines available for the treatment of these tumors, making itsmanagement a challenge for physicians. We report the case of a 53 year-old woman witha proliferating trichilemmal tumor on her nose, which is a very uncommon location forthese lesions.     

Proliferating trichilemmal cyst with clinical,radiological, macroscopic,and microscopic correlation

Proliferating trichilemmal cyst is an uncommon neoplasm arising from the follicular isthmus, whose histopathological hallmark is the presence of trichilemmal keratinization. We describe a case of proliferating trichilemmal cyst in a 57-year-old woman with a broad clinical, radiological, macroscopic and microscopic correlation.     

Proliferating trichilemmal cyst: report of two cases,one benign and the other malignant

Proliferating trichilemmal cyst (PTC) is a rare but morphologically distinct tumor that usually arises on the scalp of elderly women. We report two cases of PTC, one benign and the other malignant. PTCs are well circumscribed, subepidermal lesions and demonstrate a uniform histologic pattern with varying degrees of cytological atypia. Malignant proliferating trichilemmal cyst (MPTC) has features in common with benign proliferating trichilemmal cyst (BPTC), including a central area of abrupt keratinization and hyperplastic squamous epithelium forming solid areas. The diagnosis of MPTC is essentially based on histological features. The presence of a high mitotic rate, atypical mitosis, severe nuclear pleomorphism, and tumor invasion of the adjacent tissues are the essential histological features of malignancy in these unusual tumors. The therapeutic approach in malignant cases is the same as that in the treatment of BPTC: surgical removal with a wide clear margin. However, even with adequate resection, both tumors tend to recur locally.     

Ossifying trichilemmal cyst

Although a trichilemmal cyst is a relatively common benign cutaneous condition and ossification has been observed within many cutaneous lesions to our knowledge, the association between ossification and trichilemmal cyst has not been previously reported. We describe for the first time the case of a trichilemmal cyst with marked osseous metaplasia arising on the scalp of a 46 year-old woman. Microscopically the lesion showed the typical features of a trichilemmal cyst with the finding of intra-extraluminal foci of calcification and the exceptional feature of mature bone formation. No areas of mature cartilage were observed near the focus of ossification. The cutaneous bone may have been directly formed from osteogenic stromal elements without a cartilaginous precursor (membranous or mesenchymal ossification). The dystrophic calcification might also contribute to the bone-forming process.     

Proliferating trichilemmal cyst with focal invasion: report of a case and a review of the literature

Proliferating trichilemmal cyst (PTC) is a rare but morphologically distinctive tumor that usually occurs in the scalp of elderly women. Furthermore, only 30 well-documented examples of so-called malignant PTC have been reported. Alternatively, some authors have recently proposed that PTC is squamous cell carcinoma. We describe a case of PTC with focal invasion that was indistinguishable from squamous cell carcinoma in areas, and we review the literature. This debate should be considered in PTCs to provide adequate treatment (wide local excision) and follow-up (long term), particularly in large and long-standing lesions.     

Proliferating trichilemmal tumor with apocrine sweat glands

A 43-year-old man with a proliferating trichilemmal tumor is described. Since the tumor had appeared on a pre-existing alopecia and accompanied ectopic apocrine sweat glands, it is supposed that the pathogenesis of the tumor of our patient might be similar to that of an organoid nevus.