Ronald J. Barr

MICROCYSTIC ADNEXAL CARCINOMA, A DISTINCT CLINICOPATHOLOGIC ENTITY

Microcystic adnexal carcinoma is an unusual locally aggressive neoplasm that is important to recognize since it may be confused with benign adnexal neoplasms, particularly desmoplastic trichoepithelioma, trichoadenoma, and syringoma. Six cases are described all of which displayed benign histological features on initial biopsy. Most often these neoplasms presented as solitary flesh‐colored indurated plaques on the upper lip. All patients were white, five were women, and the average age was 44‐years‐old. Islands of basaloid keratinocytes, some of which contained horn cysts and abortive follicles, were embedded in a desmoplastic stroma. In other foci, ducts and gland‐like structures lined by a two‐cell layer predominated. In deep components individual and thin strands of cells dissected collagen bundles and skeletal muscle and invaded perineural spaces. Despite this, cytologic atypia and mitotic figures were rare. The cell of origin is considered to be a pluripotential adnexal keratinocyte which is capable of both follicular and sweat gland differentiation.

Cutaneous squamous cell carcinoma: a comprehensive clinicopathologic classification. Part One

Cutaneous squamous cell carcinoma (SCC) includes many subtypes with widely varying clinical behaviors, ranging from indolent to aggressive tumors with significant metastatic potential. However, the tendency for pathologists and clinicians alike is to refer to all squamoid neoplasms as generic SCC. No definitive, comprehensive clinicopathological system dividing cutaneous SCCs into categories based upon their aggressiveness has yet been promulgated. Therefore, we have proposed the following based upon the malignant potential of SCC variants, separating them into categories of low (≤2% metastatic rate), intermediate (3–10%), high (greater than 10%), and indeterminate behavior. Low‐risk SCCs include SCC arising in actinic keratosis, HPV‐associated SCC, tricholemmal carcinoma, and spindle cell SCC (unassociated with radiation). Intermediate‐risk SCCs include adenoid (acantholytic) SCC, intraepidermal epithelioma with invasion, and lymphoepithelioma‐like carcinoma of the skin. High‐risk subtypes include de novo SCC, SCC arising in association with predisposing factors (radiation, burn scars, and immunosuppression), invasive Bowens disease, adenosquamous carcinoma, and malignant proliferating pilar tumors. The indeterminate category includes signet ring cell SCC, follicular SCC, papillary SCC, SCC arising in adnexal cysts, squamoid eccrine ductal carcinoma, and clear‐cell SCC. Subclassification of SCC into these risk‐based categories, along with enumeration of other factors including tumor size, differentiation, depth of invasion, and perineural invasion will provide prognostically relevant information and facilitate the most optimal treatment for patients.

Primitive Polypoid Granular-cell Tumor and Other Cutaneous Granular-cell Neoplasms of Apparent Nonneural Origin

Most cutaneous and noncutaneous granular-cell tumors are currently thought to be of Schwann-cell derivation. We present seven unusual cutaneous granular-cell lesions in which Schwann-cell origin can be excluded or is inapparent. Four of these lesions are of a previously undescribed type, and, unlike conventional granular-cell tumors of the skin, show a polypoid configuration, numerous mitoses, cytologic atypia, and a primitive immunophenotype. We propose the term “primitive polypoid granular-cell tumor” for these lesions. One occurred in a child, and three in adults. There have been no metastases to date, with follow-up periods of 2, 4, 4, and 16 years, respectively, although one tumor recurred locally. Additional cases and longer follow-up may be required to rule out the possibility that primitive polypoid granular-cell tumor is a low-grade malignancy. Two other granular-cell lesions represent variants of leiomyosarcoma, one of which widely metastasized. The last case is a granular-cell form of nodular basal-cell carcinoma. Cutaneous granular-cell neoplasms can show varying differentiation and behavior. Pathologists should not equate the occurrence of cytoplasmic granularity in a cutaneous neoplasm with the diagnosis of granular-cell schwannoma.

Desmoplastic nevus. A distinct histologic variant of mixed spindle cell and epithelioid cell nevus

From a series of 75 cases of mixed spindle cell and epithelioid cell nevi, 14 were designated as desmoplastic nevi. Junctional activity, theque formation, and pigmentation were uncommon features. As a result, desmoplastic nevi may be confused with a variety of fibrohistiocytic lesions. Well defined intranuclear invaginations of cytoplasm occurred in 12 cases, and were helpful in differentiating desmoplastic nevi from these lesions. Desmoplastic malignant melanoma must also be considered in the microscopic differential diagnosis, but distinguishing features of desmoplastic melanoma include the presence of preexisting lentiginous melanoma, and necrosis of tumor cells and collagen. Desmoplastic nevus was compared to the ordinary variants of mixed spindle cell and epithelioid cell nevus in an attempt to define etiologic factors responsible for a desmoplastic reaction. No satisfactory explanation could be found since the clinical variables examined were not statistically different. Cancer 46:557–564, 1980.

Malignant neoplasms metastatic to gingivae

Malignant neoplasms metastatic to the gingivae are rare. Our review of the literature revealed only eight acceptable examples. We are reporting two additional cases. One patient was a 58-year-old man with an adenocarcinoma of the lung which metastasized bilaterally to the maxillary gingiva. The second patient was a 27-year-old man with a synovial sarcoma which metastasized to multiple sites in the maxillary and mandibular gingiva. Clinically, gingival metastatic lesions are most often confused with hemangioma, pyogenic granuloma, giant-cell granuloma, and pepripheral fibroma. They usually occur late in the course of the disease and are associated with metastatic deposits in many other organs and tissues. Death usually occurs in a few weeks or months after discovery of the gingival metastasis.

S100-positive spindle cells in scars: a diagnostic pitfall in the re-excision of desmoplastic melanoma.

Distinguishing desmoplastic melanoma (DM) from scar tissue on routine microscopy can be difficult, especially in re-excision specimens, and S100 immunohistochemistry has been recommended as a useful adjunct. The purpose of this study is to evaluate the extent and nature of S100 positivity in scars. In this study, formalin-fixed paraffin archival tissues were evaluated with immunohistochemistry. Ten re-excision specimens of previously biopsied nonnevomelanocytic lesions were immunostained with the S100 and CD57 (Leu 7) antibodies. In 9 of the 10 cases, the scars contained S100-positive spindle cells, but there were no cases with CD57+ cells. Ten re-excised atypical nevi and 10 re-excised melanomas were also immunostained for the S100 protein, and all 20 cases contained S100-positive spindle cells within the scars. There was a trend toward quantitatively more S100-positive spindle cells in these nevomelanocytic re-excisions. To evaluate the nature of the spindle cells, scars from two of the nonnevomelanocytic re-excisions were further analyzed utilizing immunostains for glial fibrillary acidic protein, HMB-45, Melan-A, CD1a, factor XIIIa, and neuron specific enolase. In both scars, neuron specific enolase diffusely stained the fibroblast population, but the remaining immunostains were negative in the scar. The presence of S100-positive spindle cells in scars represents a potential diagnostic pitfall, particularly in the evaluation of re-excision specimens of DM.

Delayed skin test reaction to injectable collagen implant (Zyderm): The histopathologic comparative study

Ten cases of persistent positive test site responses to enzyme-digested purified bovine collagen solution (EPC; Zyderm Collagen Implant) were reviewed. Specimens were stained with hematoxylin and eosin, Gomoris trichrome, colloidal iron, elastic van Gieson, Snook s reticulum, and polarized light. These granulomatous-like reactions were compared with cases of granuloma annulare, hypertrophic scarring, keloids, and rheumatoid nodules. These studies make it possible to differentiate a normal EPC implant from normal reticular dermis. The granulomatous reaction around the EPC implant can be differentiated from granuloma annulare, scars and keloids, and rheumatoid nodules. It is our conclusion that the granulomatous material is probably a combination of EPC and small amounts of altered human collagen.

Syringometaplasia: Mucinous and Squamous Variants

The eccrine sweat ducts are normally lined by cuboidal epithelial cells which may rarely undergo metaplasia, i.e. syringometaplasia. Two lesions were observed in which eccrine sweat ducts displayed the mucinous and squamous variants of syringometaplasia. The first lesion clinically and histologically appeared to be a plantar wart. Microscopically, it consisted of a central invagination surrounded by marked epidermal acanthosis and hyperkeratosis. The invagination was lined by keratinocytes admixed with mucin‐filled goblet cells. The mucin was positive by the Alcian blue (pH 2.5) and mucicarmine stains. Numerous eccrine sweat ducts led into the invagination and were focally lined by the mucin‐laden cells. Recognition of mucinous syringometaplasia is important since it may be confused with primary or metastatic adenocarcinoma of the skin. The second lesion occurred on the outer ear and was clinically believed to be chondrodermatitis nodularis helicis. Microscopically, there were many islands of atypical squamous cells within the papillary and reticular dermis. These epithelial islands represented squamous syringometaplasia since many contained central lumina with eosinophilic cuticles and blended with normal ductal structures. It is important not to confuse this metaplastic change with invasive squamous cell carcinoma. Squamous syringometaplasia may be analogous to necrotizing sialometaplasia, a recently described phenomenon which occurs in minor salivary glands.

Histologic atypia in clinically benign nevi: A prospective study

Histologic features of dysplastic nevi include varying degrees of pattern atypia, cytologic atypia, and host response. The purpose of this prospective study was to determine the prevalence of these histologic features in benign acquired nevi. Fifty-eight junctional and compound nevi from 26 volunteer subjects were excised and examined. All nevi met each of the following criteria: 5 mm or less in diameter, symmetric, round or slightly oval, uniform pigmentation, distinct and regular margins, and no erythema. One or more of the histologic features associated with dysplastic nevi were present in 87.8% of the lesions; two or more were present in 69%; and all three histologic features were found in 29.3%. These results indicate that histologic features of dysplastic nevi occur in benign common acquired nevi.

Necrobiotic granulomas associated with bovine collagen test site injections

Two patients are presented who developed persistent nodules at the test site after bovine collagen injections. Biopsies were taken, and both exhibited the histologic features of necrobiotic granulomatous inflammation.