Loss of chromosome 13 in a case of soft tissue perineurioma

Soft tissue perineuriomas are rare mesenchymal tumors that are derived from perineurial cells of the peripheral nerve sheath. Although the histological and immunohistochemical features of soft tissue perineuriomas are well described, little is known regarding the cytogenetic abnormalities in these tumors. Herein, we describe a case of a large (12.2 cm) soft tissue perineurioma that arose in the thigh of a 26-year-old Caucasian female. Histologically, the tumor was composed of a diffuse to fascicular arrangement of spindle cells with bland, elongated nuclei with long, thin, tapering cytoplasmic processes. The immunohistochemical profile was consistent with a perineurial cell origin with expression of epithelial membrane antigen, vimentin, and collagen type IV. Cytogenetic evaluation revealed loss of chromosome 13 as the sole abnormality in the majority of examined cells. In contrast to previous reports, we were unable to demonstrate deletion or structural abnormalities of chromosome 22 by either fluorescence in situ hybridization (FISH) or metaphase cytogenetics. This is the first report of loss of chromosome 13 in soft tissue perineurioma. Although never described in this group of neoplasms, loss of chromosome 13 has been identified in a large number of other soft tissue tumors, particularly sarcomas and malignant peripheral nerve sheath tumors. Herein, we discuss this case and provide a review of the literature.

CD34 expression in desmoplastic melanoma

BACKGROUND

Primary and metastatic malignant melanoma can simulate various soft tissue tumors, including dermatofibrosarcoma protuberans (DFSP). Expression of CD34, a marker characteristic of DFSP, as well as other spindle cell tumors, has not been previously documented in malignant melanoma.

METHODS

We present here an unusual case of metastatic malignant melanoma with a strong histologic resemblance to DFSP and also CD34 expression.

RESULTS

The patient, a 72-year-old man with a history of an invasive malignant melanoma of the skin of the right lower abdomen, presented with a right axillary mass. Histologic sections revealed intersecting fascicles of spindle cells with nuclear pleomorphism and numerous mitotic figures, diffusely infiltrating the adipose tissue in a pattern closely simulating that seen in DFSP. In other foci, epithelioid neoplastic cells with abundant cytoplasm, prominent nucleoli, nuclear pseudoinclusions, and focal cytoplasmic melanin pigment were seen. The neoplastic spindle cells were strongly labeled by two anti-CD34 monoclonal antibodies. Some of the spindle cells and the majority of the epithelioid neoplastic cells expressed S-100 protein and focally tyrosinase. The tumor cells were negative for HMB-45 and MART-1. Melanosomes were not identified by electron microscopy.

CONCLUSION

This case demonstrates the potential of melanoma to simulate DFSP closely, on both morphologic and immunohistochemical grounds, and confirms the utility of employing a broad panel of immunohistochemical reagents in problematic cases.

CD34 and dural fibroblasts: the relationship to solitary fibrous tumor and meningioma

Intracranial solitary fibrous tumors (SFTs) are typically dural-based, CD34-positive neoplasms of uncertain histogenesis. We examined ten cases of meninges obtained at autopsy from patients with no history of neurological illness, head trauma, or neurosurgical intervention, and ten cases of typical meningiomas with attached dural margins not involved by tumor. All cases were immunostained with CD34. CD34 reactivity was noted in the long, thin delicate processes of dural fibroblasts preferentially located in the meningeal portion of the dura rather than the periosteal portion. No CD34 reactivity was identified in the arachnoid or pia mater, except in some endothelial cells. One supratentorial dural-based fibrous nodule and one SFT within the confines of the fourth ventricle showed strong and diffuse reactivity to CD34, bcl-2, and vimentin, and were negative for epithelial membrane antigen (EMA), S-100 protein, glial fibrillary acidic protein, smooth muscle actin, and desmin. We also describe a meningothelial meningioma within which a well circumscribed SFT-like nodule was embedded. The SFT-like nodule was strongly CD34 positive and EMA negative, and the meningioma was strongly EMA positive and CD34 negative. Fibroblasts of the dural border cell layer are attached to the underlying arachnoid, and their inclusion with arachnoidal stromal elements and pial-based tela choroidea during formation of choroid plexus interstitium may account for intraventricular SFTs. Our results suggest that SFTs and dural-based fibrous nodules derive from CD34-positive dural-based fibroblasts, and that CD34 reactivity in meningiomas may result from inclusion of dural fibroblasts within the neoplasm.

Recurrent melanocytic nevus: a histologic and immunohistochemical evaluation

BACKGROUND

Recurrent melanocytic lesions may histologically resemble malignant melanoma.

METHODS

We evaluated the original nevi (ON) and recurrent nevi (RN) of 15 patients by routine histology and immunohistochemistry (IHC), examining expression of S-100 protein, gp100 (with HMB-45), MART-1, tyrosinase, and the Ki-67 proliferation marker.

RESULTS

Compared with ON, RN had a dermal scar, a significantly greater number of melanophages, and a greater extent of cellular atypia including prominent nucleoli and larger cell size. Architecturally, RN showed significantly less symmetry than ON; however, the percentage of junctional cohesive nests, the presence of suprabasal spread, and the degree of confluence were similar between ON and RN. Both ON and RN showed a decrease in expression of gp100 and tyrosinase with increasing depth ("maturation gradient") and low proliferative activity in both the junctional (4.6% for ON vs. 4.13% for RN) and the dermal components (0.93% for ON vs. 1.45% for RN).

CONCLUSIONS

RN exhibit a dermal scar, a greater number of melanophages, cytologic atypia, and asymmetry than ON, features that may raise concern about the possibility of malignant melanoma. However, the area with the irregular architectural pattern is restricted to the epidermis and dermis immediately above the scar. In addition, IHC helps to distinguish RN from malignant melanoma; specifically, RN demonstrate an immunohistochemical "maturation pattern" (with HMB-45 and anti-tyrosinase) and a low proliferative index (with Ki-67).

Malignant melanoma with paradoxical maturation

Typically, melanocytic nevi "mature" (i.e., exhibit a morphologic shift to smaller or spindle cells with progressive depth in the dermis). In contrast, most malignant melanomas (conventional MMs) lack maturation, and are composed of large pleomorphic cells throughout. The authors describe a series of melanomas with paradoxical maturation mimicking the pattern of nevi. Seventeen primary invasive melanomas with paradoxical maturation (IMPs), two epidermotropic metastatic melanomas with maturation (EMMMs), 13 compound nevi (CN), and 14 conventional MMs without apparent maturation were analyzed by histologic, cytomorphometric, and immunohistochemical techniques. With increasing dermal depth, both CN and IMPs had smaller nuclear and cellular areas, and decreased expression of Ki-67, glycoprotein (gp)100 (with HMB-45), and tyrosinase. IMPs had significant differences from conventional MMs; namely, smaller nuclear and cytoplasmic areas (deep), and decreased expression of Ki-67 (superficial and deep), gp100 (deep), and tyrosinase (deep). IMPs also had notable differences from CN: namely, larger nuclear and cellular areas, more confluence, more mitotic figures, increased Ki-67 and gp100 expression in both the superficial and deep portions, and more melanin (deep). The two EMMMs exhibited histologic and immunohistochemical features similar to the primary IMPs. IMP, because of its mimicry of nevus, can present a diagnostic hazard. The authors propose histologic, morphometric, and immunohistochemical criteria that facilitate recognition and accurate diagnosis of this unusual variant of melanoma.

Keratotic melanocytic nevus: a clinicopathologic and immunohistochemical study

BACKGROUND

Epidermal hyperplasia in melanocytic nevi is a common but little-investigated phenomenon.

METHODS

We prospectively examined all melanocytic nevi diagnosed in our department over an 8-month period, for the criteria of keratotic melanocytic nevus (KMN), namely the presence of marked epidermal hyperplasia with or without horn pseudocyst formation, hyperkeratosis, and papillomatosis. In addition to routine histologic review, we studied 12 representative cases with immunohistochemistry to examine expression of Ki-67, epidermal growth factor receptor (EGFR), Bcl-2, and Bax.

RESULTS

From a total of 1,527 melanocytic nevi, 95 were KMN (prevalence 6%). The average age was 34 years, with a male:female ratio of 1:2. The predominant location was the trunk (76%), followed by head and neck (20%), and extremities (4%). Clinical diagnoses were atypical nevus (44%), nevus not otherwise specified (43%), and others including seborrheic keratosis, acrochordon, and basal cell carcinoma. Two KMN were junctional, 44 compound, and 49 intradermal. Twenty-three KMN (24%) had histologic features suggesting congenital onset, and 15 (16%) had mild to moderate dysplastic features. Two cases demonstrated induction of sebaceous glands. Significantly increased Ki-67 expression was detected in the hyperplastic epidermis, particularly in deeper areas related to keratinous cysts and hair follicles. Bcl-2 and Bax (anti- and pro-apoptosis proteins, respectively) and EGFR were expressed similarly in both normal and hyperplastic epidermis overlying the KMN.

CONCLUSIONS

KMN are commonly biopsied skin lesions, mostly located on the trunk. Many such lesions are clinically considered atypical, in contrast to their benign histologic appearance. The epidermal hyperplasia on top of KMN demonstrates increased cellular proliferation, in the context of adequately regulated apoptosis and EGFR expression. The cellular proliferation seems to commence in hair follicles.

Indeterminate fibrohistiocytic lesions of the skin: is there a spectrum between dermatofibroma and dermatofibrosarcoma protuberans?

Routine histology and immunohistochemistry can usually distinguish dermatofibroma (DF) and dermatofibrosarcoma protuberans (DFSP). DF generally expresses factor XIIIa whereas DFSP generally expresses CD34. The authors report 10 cutaneous fibrohistiocytic lesions combining clinical, histologic, and immunohistochemical features of both DF and DFSP. The lesions had an average size of 1.2 cm (range, 0.4-2.7 cm), and occurred on the trunk (n = 6), extremities (n = 3), and face (n = 1) of four men and six women (average age, 30.6 yrs; age range, 15-50 yrs). Eight lesions exhibited acanthosis and densely cellular fascicles with focal storiform areas. All had keloidal collagen, infiltrated the subcutis in a honeycomb pattern, and had low mitotic counts (0 to 4 mitoses per square millimeter). All were diffusely immunoreactive for factor XIIIa (30%-60% of the neoplastic cells) as well as CD34 (20%-70%). This series raises the possibility of a biologic spectrum between DF and DFSP; however, double-immunolabeling studies showed no notable coexpression of factor XIIIa and CD34 by individual cells, suggesting coexistence of two different cellular populations. After an average follow up of 22.3 months (range, 10-46 mos) in six cases, a single recurrence was documented. The ambiguous histologic features and the potential for local recurrence suggest that performing a complete excision may be prudent in these diagnostically indeterminate lesions.

Extramammary Paget disease is characterized by the consistent lack of estrogen and progesterone receptors but frequently expresses androgen receptor

Extramammary Paget disease (EPD) is an uncommon cutaneous malignant neoplasm that arises in areas rich in apocrine glands (perineum, vulva, and axilla). Apocrine gland origin or apocrine differentiation of cells of EPD has been suggested. Estrongen, progesterone, and androgen hormone receptors have been reported to exhibit a characteristic pattern of expression in mammary apocrine type carcinomas; however, their expression in EPD has not been elucidated fully. By using immunohistochemical methods, we studied the expression of steroid receptors in EPD on formalin-fixed paraffin-embedded tissue samples from 28 patients with EPD without associated visceral malignant neoplasms or adnexal carcinoma. Androgen receptor (AR) was identified in 15 of 28 cases. The proportion of AR-positive cells varied from 1% to more than 75%; 8 cases expressed AR in more than 10% of cells. Strong AR expression also was seen in the invasive carcinoma arising from 1 case of EPD. All cases lacked immunohistochemically detectable estrogen and progesterone receptors. The immunophenotype characteristic of apocrine carcinomas (AR-positive, estrogen receptor-negative, progesterone receptor-negative) was seen in a substantial proportion of EPD cases. Results suggest that AR expression is a factor in pathogenesis of EPD. This may be important for the therapy of recurrent or invasive disease.

Expression of the intermediate filament peripherin in extraskeletal myxoid chondrosarcoma

The embryologic histogenesis of cartilage is not well characterized. While cranial cartilage is believed to be derived from pluripotential precursor cells of the neural crest, chondrocytes found elsewhere in the body are thought to be derived from mesoderm. As such, soft tissue tumors with cartilaginous differentiation may be related to neural crest or mesoderm. Peripherin is an intermediate filament encoded on chromosome 12, involved in growth and development of the peripheral nervous system. Peripherin is apparently expressed exclusively in cells derived from the neural crest and neural tube. A group of six soft tissue tumor types was selected because they are either of controversial differentiation or cytogenetically related to chromosome 12. A total of 41 cases was evaluated with antibodies against the intermediate filament peripherin. A panel of neural and neuroendocrine differentiation markers was used in selected cases. Three of five extraskeletal myxoid chondrosarcomas showed strong cytoplasmic reactivity with anti-peripherin. No peripherin expression was noted in any of eleven epithelioid sarcomas, eight liposarcomas, seven conventional chondrosarcomas, four neurothekeomas, three alveolar soft part sarcomas, or three clear cell sarcomas. The finding of peripherin expression in some extraskeletal myxoid chondrosarcomas may suggest the ability of some tumors to demonstrate both neural and chondroid differentiation.

Primary central nervous system lymphomas: a 30-year experience at a single institution

Primary central nervous system lymphoma (PCNSL) is a rare disease that has been increasing in frequency. Clinical, histologic, and immunohistochemical data from 64 cases of PCNSL seen at Duke University Medical Center since 1968 were reviewed and tumors were classified using the REAL classification system. Thirty-two patients were male and 32 were female, with a mean age of 57.1 years, ranging from 16 to 82 years. Large B-cell lymphoma represented overwhelming the majority of PCNSL, accounting for 81% of all cases. Phenotypic T-cell lymphomas were rare with only two cases over the course of the study. Epstein-Barr virus was detected only in the immunocompromised patients and was identified in 75% of those immunocompromised patients who were tested. Overall survival was poor with a mean survival of 357 days and median survival of 158 days. One- and three-year survival rates were 29.6% and 7.8%, respectively. Type of treatment, duration of symptoms, site of lesion, and histologic subtype were not significant prognostic indicators, whereas concurrent immunosuppression was the strongest predictor of poor outcome. In AIDS patients (which accounted for 21.9% of the study group), the median survival was 65 days, which was significantly different than that seen in the immunocompetent group of 217 days (P = .001).

Diagnosis and management of BK polyomavirus interstitial nephritis in renal transplant recipients

BACKGROUND

Interstitial nephritis caused by BK polyomavirus is a recognized complication of renal transplantation. A study of renal transplant recipients at Duke University Medical Center was undertaken to evaluate diagnostic modalities and assess clinical outcomes in transplant polyomavirus infections.

METHODS

Polyomavirus nephritis was identified in 6 of 240 patients who received renal transplants between January 1996 and June 1998 and an additional patient who underwent transplantation in 1995. The clinical records of these seven patients were reviewed, as were all renal biopsy and nephrectomy specimens. Electron microscopy (EM) was performed on negatively stained urine samples from 6 patients with polyomavirus infection and 23 patients with other diagnoses.

RESULTS

Patients with polyomavirus infection shared several clinical features, including ureteral obstruction (5/7 patients), lymphocele (3/7), bacterial urinary tract infection (3/7), hematuria (3/7), cytomegalovirus infection (3/7), and immunosuppression with mycophenolate mofetil (6/7). All patients experienced elevations in serum creatinine, which stabilized or decreased in four patients with altered or decreased immunosuppression. The diagnosis of polyomavirus infection was established by renal biopsy and EM of urine in five patients, by biopsy alone in one, and by EM alone in one. Sequential examinations of urine by EM were used to monitor the course of infection in six patients.

CONCLUSIONS

Interstitial nephritis due to BK polyomavirus occurred in 2.5% of patients receiving renal transplants at our center since 1996. Polyomavirus infection can cause transplant dysfunction and graft loss, but progression of the infection can frequently be abrogated with alterations in immunosuppressive therapy. Both renal biopsy and EM of urine samples are useful in the diagnosis and monitoring of polyomavirus infections.

Progesterone receptor activity in leiomyomatosis peritonealis disseminata

Leiomyomatosis peritonealis disseminata (LPD) is a rare condition that primarily affects women of reproductive age. Immunohistochemical studies were performed in four cases: LPD from a premenopausal woman on oral contraceptives (one case); LPD associated with postpartum massive ectopic decidual reaction (one case); and LPD from a perimenopausal and a postmenopausal woman. Progesterone receptor activity was present in nine of nine cases, and eight of eight cases were strongly positive for vimentin; reactivity for cytokeratin was uniformly negative. Most cases had a pattern of staining typical of smooth muscle tumors with expression of desmin, smooth muscle actin, and muscle-specific actin. Although estrogen receptor was detected in most cases, reactivity was notably absent (one case) or weak (one case) in nodules with a prominent decidual reaction. Expression of CD 34, a marker for which LPD staining characteristics have not been previously reported, varied from absent to weak. Peritoneal nodules from the postmenopausal woman lacked staining for both estrogen receptor and desmin, smooth muscle actin and muscle-specific actin were only focally expressed, whereas staining for CD 34 was focally intense. Uterine myometrium and leiomyomata were positive for progesterone and estrogen receptor, vimentin, desmin, smooth muscle actin, and muscle-specific actin. Cytokeratin expression was absent. CD 34 exhibited weak staining in leiomyomata, but was absent from myometrium. Progesterone receptor appears to be uniformly expressed in LPD nodules from premenopausal and postmenopausal women, a finding supporting the contention that hormones influence the development of LPD in all cases, regardless of menopausal status.

Desmoplastic (sclerotic) nevus: an underrecognized entity that resembles dermatofibroma and desmoplastic melanoma

Desmoplastic (sclerotic) nevus, a benign melanocytic neoplasm characterized by predominantly spindle-shaped nevus cells within a fibrotic stroma, can be confused with fibrous lesions and other melanocytic proliferations, including desmoplastic melanoma. We compared the histologic and immunohistochemical features of 16 desmoplastic nevi, nine desmoplastic melanomas, four hypopigmented blue nevi, and six dermatofibromas. The similarities between desmoplastic nevi and dermatofibromas included epidermal hyperplasia (12 of 16), presence of keloidal collagen (15 of 16), hypercellularity (16 of 16), and increased numbers of factor XIIIa-positive dendritic cells (12 of 12). The absence of adnexal induction (0 of 16), the rarity of lesions with multinucleated cells (3 of 16) or epidermal hyperpigmentation (2 of 16), and the presence of S-100 immunoreactivity (16 of 16) and melanocytic proliferation (9 of 16) helped differentiate desmoplastic nevi from dermatofibromas. The similarities between desmoplastic nevi and desmoplastic melanomas included the presence of atypical cells (16 of 16) and HMB-45 expression in the superficial portion of the lesions (11 of 16). The infrequent location on the head or neck (1 of 16), the absence of mitotic figures (0 of 16), a significantly lower number of Ki-67-reactive cells, and a decrease in HMB-45 expression in the deep area of the lesions (8 of 11) helped distinguish desmoplastic nevi from desmoplastic melanoma. Desmoplastic nevi had overlapping features with hypopigmented blue nevi, but features tending to favor the latter included a predominance of ovoid nuclei, higher numbers of atypical cells, and homogeneous staining with HMB-45. We conclude that a combination of histologic and immunohistochemical criteria facilitates the reliable diagnosis of desmoplastic nevus from its simulators.

High-intensity flashlamp photoepilation: a clinical, histological, and mechanistic study in human skin

OBJECTIVE

To examine the clinical, histological, and immunohistological effects of flashlamp photoepilation.

DESIGN

Nonrandomized control trial with blinded histological study and follow-up of 1 to 20 months.

SETTING

Private academic practice.

SUBJECTS

Sixty-seven subjects (10 males and 57 females) with areas of excess body hair.

INTERVENTIONS

Single (9 subjects) or multiple (58 subjects) treatments (noncoherent, 590-1200 nm, 2.9-3.0 milliseconds, 40-42 J/cm2) to hairy skin. From subjects given a single treatment, biopsy samples were taken immediately after treatment and at different intervals for up to 20 months.

MEAN OUTCOME MEASURES

Clinical measures include hair counts and morphologic features before and after treatment. Histological measures include terminal-vellus and anagen-other ratios, hair shaft diameter, and morphologic features (routine and immunohistochemical detection of bcl-2, bax, p53, Ki67, cyclin D1, and hsp70) before and after treatment.

RESULTS

Mean hair loss after photoepilation was 49%, 57%, and 54% for a single treatment and 47%, 56%, and 64% for multiple treatments at follow-up of less than 3 months, 3 to less than 6 months, and 6 months or longer, respectively (P<.05 for all comparisons). Transient erythema was seen in all subjects; no scarring occurred. Histologically, treatment caused morphologic damage confined to hair follicles and shafts. Terminal-vellus and anagen-telogen ratios, mean hair shaft diameter, and immunohistochemical profiles were not significantly modified by treatment. Treatment did not alter other skin adnexa, epidermis, or vessels.

CONCLUSIONS

Flashlamp treatment leads to significant, longlasting epilation. The predominant mechanism seems to be via selective photothermal damage to large, pigmented hair follicles rather than induction of a programmed state of follicular cycle arrest or follicular miniaturization.

Quantitation of intraepidermal T-cell subsets in formalin-fixed, paraffin-embedded tissue helps in the diagnosis of mycosis fungoides

Differentiation between mycosis fungoides (MF) and cutaneous inflammatory processes can usually be made on clinical and histologic grounds. In difficult cases, immunohistochemical studies can be helpful since MF infiltrates usually contain a predominance of CD4+ lymphocytes, while most inflammatory lesions usually have a mixture of CD4+ and CD8+ lymphocytes. However, this determination has traditionally required the use of frozen tissue, thus severely limiting its usefulness. Recently, antibodies that differentially label CD4+ and CD8+ lymphocytes in formalin-fixed, paraffin-embedded tissue have become available (OPD4 and C8/144B respectively, DAKO (Carpinteria, CA, USA). This study tests the utility of these antibodies in the pathologic diagnosis of MF and inflammatory lesions with significant exocytosis. In 9 cases of MF for which both frozen and fixed tissues were available for comparison, the OPD4+ cell count in fixed tissue was significantly lower than the Leu-3a+ cell count in frozen tissue. Also, the C8/144B+ cell count in fixed tissue was higher than the Leu-2a+ cell count in frozen tissue, although this difference was not significant statistically. In a larger series for which only fixed tissue was available, epidermal CD4:CD8 ratios were significantly greater in 23 MF cases (mean 4.0+/-4.76) than in 35 inflammatory cases (mean 0.6+/-0.42; p = 0.001). Thus, although the studied antibodies appear to detect different epitopes in frozen versus paraffin-embedded tissue, demonstration of an elevated CD4:CD8 ratio in fixed tissue supports the diagnosis of MF, and is a helpful adjunct to routine histopathology.

Middle ear carcinoid: an indolent tumor with metastatic potential

BACKGROUND

Neuroendocrine tumors of the head and neck region may present problems in diagnosis. Middle ear carcinoid is a rare, recently recognized tumor, which to date has not been reported to metastasize.

METHODS

We report the case of a 64-year-old man with a 9-year history of recurrent middle ear neoplasm and ipsilateral cervical lymphadenopathy. A microscopic parathyroid tumor was also identified. The approach to the diagnosis of this unusual combination is presented.

RESULTS

The patient had a neuroendocrine tumor metastatic to multiple unilateral cervical lymph nodes, which was morphologically identical to his recurrent middle ear neoplasm. The neoplasm had the morphologic, immunohistochemical, and ultrastructural features of a carcinoid tumor.

CONCLUSIONS

This case illustrates that middle ear carcinoids may metastasize. We suggest that immunohistochemical studies be performed on all biopsy specimens from neoplasms of the middle ear, as distinction from the more common paraganglioma may be difficult on morphologic grounds alone.

Multiple myeloma-associated amyloidosis and giant cell arteritis

Primary systemic amyloidosis has been associated with the development of symptoms and clinical features characteristic of polymyalgia rheumatica and/or giant cell arteritis (GCA). Case reports of this clinical entity have been published, stating that the amyloid deposition leads to the symptoms of vasculitis. In this report, we present a second case in the English literature of a patient presenting with multiple myeloma-associated amyloidosis and GCA. This is the first case in which the histopathologic findings are described in enough detail to suggest a pathogenic relationship between the two diseases.

Endothelial metaplasia in the iridocorneal endothelial syndrome

PURPOSE

To test the hypothesis that the aberrant, cytokeratin-expressing cells that replace endothelium in the iridocorneal endothelial (ICE) syndrome are of endothelial origin.

METHODS

Corneas from four patients with Chandler's syndrome and three with essential iris atrophy were examined by two-color immunofluorescence for simultaneous expression of cytokeratins and two markers of endothelial lineage: vimentin and the antigen recognized by the antiendothelial monoclonal antibody 2B4.14.1.

RESULTS

In six corneas, unequivocal endothelial staining for cytokeratins was present; in each of these, cells coexpressing cytokeratins and the two endothelial markers were clearly identifiable. In the remaining cornea, weak cytokeratin staining that colocalized with vimentin was present.

CONCLUSIONS

These results lend strong support to the hypothesis that the "epithelial-like" endothelial cells in ICE syndrome are cells of endothelial lineage rather than heterotopia of epithelial cells; these cells probably arise via a metaplastic transformation of preexisting endothelium.

Immunoperoxidase and immunofluorescent staining of Rickettsia rickettsii in skin biopsies. A comparative study

OBJECTIVE

To compare immunofluorescent and immunoperoxidase staining of Rickettsia rickettsii in skin biopsies of patients suspected of having Rocky Mountain spotted fever (RMSF).

DESIGN

Immunofluorescent staining results for R rickettsii from skin biopsies of patients suspected of having RMSF were obtained by computer and chart review. Immunoperoxidase staining for R rickettsii was performed on formalin-fixed, paraffin-embedded skin biopsies from the same patient population.

PATIENTS

Twenty-six patients who were clinically suspected of having RMSF were included in this study. Skin biopsies of these patients were examined for evidence of RMSF by immunofluorescence and routine histology.

MAIN OUTCOME MEASURES

The sensitivity and specificity of both immunofluorescent and immunoperoxidase staining techniques were calculated. The chi 2 method was used to assess significance.

RESULTS

Both tests were highly significant for the detection of R rickettsii (P < .01). The sensitivity and specificity of the immunofluorescent and immunoperoxidase staining techniques for the identification of RMSF were identical. No significant difference between these tests was identified (P > .05).

CONCLUSION

The sensitivity and specificity of immunofluorescent and immunoperoxidase staining of R rickettsii in routinely processed, paraffin-embedded skin biopsies of patients suspected of having RMSF are identical. Although not as rapid as the immunofluorescent technique, immunoperoxidase staining of R rickettsii has advantages over the immunofluorescent technique; these include easier antigen localization and concomitant viewing of the corresponding histopathology.

Adherence of Helicobacter pylori to areas of incomplete intestinal metaplasia in the gastric mucosa

BACKGROUND & AIMS

Helicobacter pylori is not usually found in areas of intestinal metaplasia. Thus, the development of intestinal metaplasia has been viewed as a mechanism by which the stomach eliminates H. pylori. The aim of this study was to evaluate the frequency of H. pylori adherence to intestinal metaplasia in different populations.

METHODS

Mapped gastric biopsy specimens from 378 H. pylori-positive subjects from various geographical regions were examined. Intestinal metaplasia was typed by staining with periodic acid-Schiff/alcian blue and high-iron diamine/alcian blue.

RESULTS

In 32 patients, H. pylori was found in intimate contact with intestinal metaplasia. This was documented by electron microscopy. All areas of intestinal metaplasia showing adherence contained sulfomucins and had no brush border. Posttreatment biopsy specimens from 4 patients whose infection was not cured showed persistence of H. pylori in intestinal metaplasia.

CONCLUSIONS

These patients may have a strain of H. pylori with unusual adhesion characteristics, or their type of intestinal metaplasia may have biochemical properties that make it hospitable for H. pylori. The exclusive association of H. pylori adherence with incomplete intestinal metaplasia (a putative precursor of carcinoma) and its greater frequency in Koreans (a population at risk for gastric cancer) suggest that this phenomenon may play a role in the hypothetical sequence metaplasia > dysplasia > carcinoma.

Tissue transglutaminase expression in human breast cancer

Tissue transglutaminase (tTG) is postulated to play a role in apoptosis, cell adhesion, metastasis, and extracellular matrix (ECM) assembly. In this study, the distribution and expression of tissue transglutaminase was investigated in normal human mammary tissue and in intraductal and invasive human breast cancer by immunohistochemistry and in situ hybridization. Frozen and formalin-fixed paraffin-embedded sections of normal, intraductal, and invasive human breast carcinoma were examined with an avidin-biotin complex immunoperoxidase method for tTG antigen and by in situ hybridization to determine the cell types expressing tTG mRNA. The expression of tTG in normal and malignant mammary epithelium in culture was evaluated by quantitative immunoblot analysis. Low-level expression of tTG was found in normal tissues with the antigen located in the ECM surrounding the ducts and in the endothelium. In intraductal cancer, there was a marked increased expression of the tTG antigen, and the increased staining was found in the ECM and was also localized in a distinct pattern at the boundary between the in situ tumor cells and the normal tissue. Further immunohistochemical analysis revealed that the cells in this boundary also stained for the endothelial cell markers CD31, CD34, and von Willebrand factor. In invasive tumors, the tTG antigen was no longer localized to the normal tissue/tumor boundary but dispersed around the tumor cells. In situ hybridization studies revealed three distinct compartments of tTG synthesis: (a) tumor cells, (b) endothelial cells, and (c) stromal cells. In addition, normal and malignant epithelial cells in culture expressed variable amounts of tTG, and the expression of tTG in these epithelial cells was at least 17-fold less than endothelial cells. The up-regulation of tTG in intraductal and invasive human breast cancer and its localization to the ECM and neovasculature suggest that tTG may regulate tumor growth and metastasis.

Eccrine gland infiltration by mycosis fungoides

After identifying prominent eccrine infiltration by atypical lymphocytes in a biopsy of tumor stage mycosis fungoides (MF), we sought to determine the pattern of eccrine epithelial infiltration in MF. The frequency, intensity, and distribution of infiltration of eccrine gland structures, including acrosyringium, duct and coil epithelium, was studied by examining 71 biopsy specimens from 42 patients with MF in which eccrine structures were present. These were obtained from a retrospective review of pathologic specimens from Duke University Medical Center from 1992 and 1993. At least focal eccrine infiltration was noted in 23 of the 71 biopsy specimens (32%). Immunohistochemical confirmation of T-lymphocyte phenotype was performed in the 23 cases with positive reaction to antibodies CD3 and CD45RO and negative reaction with CD20. Folliculosebaceous units were present in 22 of the 71 biopsy specimens and were at least focally involved by MF in 11 (50%) in this series. A control group of biopsy specimens of reactive dermatoses were characterized by more superficial location of lymphocytes, with more spongiosis and epithelial degenerative changes. These findings further illustrate the epitheliotropic behavior of MF.

Cytomegalovirus keratitis after penetrating keratoplasty

We report the development of cytomegalovirus (CMV) keratitis in the penetrating keratoplasty of a 59-year-old human immunodeficiency virus-negative woman after uncomplicated corneal transplantation. Immunosuppression with topical cyclosporine A 2% in corn oil and topical prednisolone acetate 1% suspension was used postoperatively. The 15-month postoperative course was complicated by multiple episodes of endothelial rejection, medically controlled elevated intraocular pressure, polymicrobial bacterial (coagulase-negative staphlococcus and alpha-hemolytic streptococcus) keratitis, and endothelial plaque formation with associated hypopyon and epithelial defect. The graft failed and penetrating keratoplasty was repeated. Cytomegalovirus infection of superficial keratocytes in a region of scarring was identified in histological sections stained with hematoxylin and eosin and confirmed using mouse monoclonal anti-cytomegalovirus antibodies. Excision of the diseased corneal button with no additional treatment appears to have been curative. Low-grade keratitis was the only manifestation of the CMV infection, and it has not recurred 6 months postoperatively.

Ber-EP4 immunoreactivity in normal skin and cutaneous neoplasms

Ber-EP4 is an antibody raised against a cell membrane glycoprotein of, as yet, unknown function. In the skin, the ability to distinguish basal cell carcinoma from squamous cell carcinoma has been emphasized. Immunoreactivity in apocrine and eccrine secretory coil epithelium, Merkel cell carcinoma, and cutaneous mixed tumor has been reported. Having observed more widespread staining than previously reported, we sought to characterize further Ber-EP4 immunoreactivity by examining 76 formalin-fixed and paraffin-embedded proliferative epithelial skin lesions, 2 sections of fetal skin with developing adnexa, and frozen sections of skin from Mohs surgery procedures, using hematoxylin and eosin and Ber-EP4 immunostaining. In paraffin-embedded skin, matrical and outer sheath epithelium of vellus anagen follicles, inferior segment epithelium of vellus telogen follicles, and secretory coils of sweat glands stain with Ber-EP4, but anagen terminal follicle epithelium and eccrine and apocrine sweat ducts are negative. On frozen section, additional staining of eccrine ducts and cells in the outer sheath and matrix of the inferior segment of terminal follicles is noted. Basaloid epithelium of trichoepitheliomas, follicular induction over dermatofibromas, mammary Paget's disease, and selected other neoplasms showing eccrine or apocrine differentiation stain with Ber-EP4. These data indicate that in addition to basal cell carcinoma, Ber-EP4 staining may be seen in a variety of proliferative epidermal and adnexal lesions.

Immunoreactive Prostatic Specific Antigen in Male Periurethral Glands

Prostatic specific antigen (PSA) is considered an antigen unique to benign and malignant prostatic tissue. Recent evidence in the literature has raised serious doubts about the specificity of this antigen. In this study twenty male urethral specimens were evaluated for PSA and prostatic acid phosphatase (PAP) from patients without evidence of prostatic cancer. Eight of these 20 urethral specimens exhibited strong immunostaining for both PSA and PAP, localized in the periurethral glands. Five of the 17 urethral biopsies were positive for both antigens, while all three of the whole mount autopsy specimens stained positive for PSA and PAP. Within the autopsy series, there was heterogenous staining of the periurethral glands within the same specimen. This evidence disproves the fact that PSA and PAP are organ specific as previously described. More than likely any tissue of cloacal origin has potential for staining positive for prostatic specific antigen and prostatic acid phosphatase.

Characterization of a novel human corneal endothelial antigen

The antigenic composition of the human corneal endothelium, a cellular layer essential for maintaining corneal function, has not been well characterized. A novel corneal endothelial antigen was identified by generating a monoclonal antibody (MAb) against normal human corneal endothelial cells. This MAb, designated 2B4.14.1, reacted strongly by immunoperoxidase staining with the endothelium of corneas from all human donors tested but not with other corneal components, including epithelium and stroma. Positive immunohistologic reactions of 2B4.14.1 with several other human tissues, including kidney (parietal epithelium of Bowman's capsule, proximal convoluted tubule, ascending limb of Henle's loop, and distal convoluted tubule), glandular epithelia of numerous organs, and mesothelial linings of several thoracic and abdominal viscera, also were observed. One of the renal antigens recognized by 2B4.14.1 was identified as Tamm-Horsfall glycoprotein (THGP), based on the ability of the antibody to recognize THGP in western immunoblots and the abrogation of immunohistologic reactivity of the antibody by preincubation with purified THGP. These findings raise the possibility that the human cornea expresses a molecule with homeostatic properties similar to those ascribed to THGP. However, it is unlikely that the corneal antigen recognized by 2B4.14.1 is conventional THGP; a MAb specific for THGP did not react with corneal endothelium.

Exocrine pancreatic tissue in human liver: a metaplastic process?

Numerous microscopic foci of exocrine pancreatic tissue consisting of acini and small ductules were distributed throughout the liver of a 41-year-old patient with severe posthepatitic cirrhosis. The acinar cells were characterized by abundant zymogen granules on electron microscopic examination and a strong reaction with antibodies to alpha-amylase on immunoperoxidase staining. The pancreatic tissue was associated with proliferations of bile ductules within areas of fibrosis. No relationship with hepatocytes was observed. A metaplastic origin of the pancreatic tissue from the intrahepatic biliary epithelium is suggested.

Histopathologic and immunochemical features of lattice corneal dystrophy type III

We examined seven corneas from five patients with a new form of lattice corneal dystrophy (designated lattice corneal dystrophy type III) by light and electron microscopy. Numerous amyloid deposits were scattered throughout the corneal stroma, some of which were much larger than those usually observed in either lattice corneal dystrophy type I or II; these were located predominantly midway between the epithelium and the endothelium. Image analysis disclosed that the cross-sectional size of the large stromal amyloid deposits was significantly greater than those in age-matched patients with lattice corneal dystrophy type I. All patients had a discontinuous band of amyloid (15 to 25 micron wide) in the superficial stroma beneath Bowman's layer, which usually had only one or two small disruptions. Descemet's membrane and the endothelium were normal. The stromal deposits, which were composed of 10-nm diameter fibrils typical of amyloid, stained positively with Congo red after the histologic sections were pretreated with dilute potassium permanganate. Immunohistochemical studies on formalin-fixed, paraffin-embedded tissue indicated that only some deposits reacted weakly with antibodies to amyloid protein AA. The deposits stained positively with antibodies to protein AP and negatively with antibodies to kappa and lambda immunoglobulin light chains.

A rapid method for immunofluorescent staining of paraffin sections using iron-containing protein A microspheres

A method to rapidly perform immunofluorescence or light microscopic staining on formalin-fixed paraffin sections has been devised utilizing magnetic albumin microspheres containing Staphylococcal protein A. Because the protein A constituent of the microspheres has the property of binding the Fc portion of immunoglobulin G (IgG) class antibodies, the microspheres can be used to rapidly bind antigen-antibody complexes by the Fc portion of the antibody. Deparaffinized sections were stained with fluorescein isothiocyanate-conjugated antibody (IgG fractions) by standard techniques, after which the protein A microspheres were layered over the sections. Distinct fluorescence of sections was noted with the addition of the microspheres, whereas only autofluorescence was present with direct staining alone. The microspheres were also visualized by light microscopy by a subsequent Prussian blue reaction, staining the Fe3O4 within the microsphere matrix. This method represents a more rapid method for identifying antigens in tissues embedded in paraffin than has previously been reported.