Localized amyloidosis in basal cell carcinoma. A pathologic study

A review: Exploring the metabolic and structural characterisation of beta pleated amyloid fibril in human tissue using Raman spectrometry and SAXS

Amyloidosis is a deleterious condition caused by abnormal amyloid fibril build-up in living tissues. To date, 42 proteins that are linked to amyloid fibrils have been discovered. Amyloid fibril structure variation can affect the severity, progression rate, or clinical symptoms of amyloidosis. Since amyloid fibril build-up is the primary pathological basis for various neurodegenerative illnesses, characterization of these deadly proteins, particularly utilising optical techniques have been a focus. Spectroscopy techniques provide significant non-invasive platforms for the investigation of the structure and conformation of amyloid fibrils, offering a wide spectrum of analyses ranging from nanometric to micrometric size scales. Even though this area of study has been intensively explored, there still remain aspects of amyloid fibrillization that are not fully known, a matter hindering progress in treating and curing amyloidosis. This review aims to provide recent updates and comprehensive information on optical techniques for metabolic and proteomic characterization of β-pleated amyloid fibrils found in human tissue with thorough literature analysis of publications. Raman spectroscopy and SAXS are well established experimental methods for study of structural properties of biomaterials. With suitable models, they offer extended information for valid proteomic analysis under physiologically relevant conditions. This review points to evidence that despite limitations, these techniques are able to provide for the necessary output and proteomics indication in order to extrapolate the aetiology of amyloid fibrils for reliable diagnostic purposes. Our metabolic database may also contribute to elucidating the nature and function of the amyloid proteome in development and clearance of amyloid diseases.

AA Amyloidosis associated with cancers

Systemic AA amyloidosis is associated with systemic inflammatory processes such as autoimmune disorders or chronic infections. In addition, AA amyloidosis can develop in a localized or systemic form in patients with malignant neoplastic disorders, and usually involves kidneys impacting renal function. Among solid tumors, renal cell carcinoma (RCC) appears to be responsible for one-quarter to half of all cancers associated with amyloidosis. Among other solid cancers, various clinical presentation and pathological types of lung cancer and basal cell carcinoma skin were reported with AA amyloidosis more often than isolated case reports on other cancers with AA amyloidosis. Symptoms from kidney involvement rather than from the tumor per se were the presenting manifestations in cases of RCC associated with AA amyloidosis. Among hematological malignancies, clonal B cell/plasma cell dyscrasias such as monoclonal gammopathy and lymphoma were noted to be associated with AA amyloidosis. In addition, AA amyloidosis was reported in a substantial number of cases treated with immune checkpoint inhibitors such as pembrolizumab and nivolumab. The mechanism of association of cancer and AA amyloidosis seems to be mediated by the immune response exacerbated from the tumor and its microenvironment or immune therapy. The mainstay of treatment consists of therapy directed against the underlying malignancy or careful withdrawal of the offending agent. This review will discuss this rare but highly morbid clinical condition.

Basal Cell Carcinoma Associated with Secondary Localized Cutaneous Amyloid Deposits: Case Report and Review

Amyloid deposition has been observed in tissue specimens of basal cell carcinomas. A 68-year-old man with a nodular basal cell carcinoma on his left arm near the elbow is described; microscopic evaluation of the biopsy tissue specimen shows not only nodular aggregates and strands of atypical basaloid tumor cells but also marked deposition of amorphous amyloid material in the stroma between the aggregates of basal cell carcinoma. Including the man in this report, there are additional individual descriptions of patients whose basal cell carcinomas have amyloid deposits in the adjacent stroma or within the tumor aggregates or both. In addition, several retrospective pathology investigations have evaluated the features of this phenomenon. The incidence of basal cell carcinoma with amyloid deposition, in the English literature, ranges from 11% to 75%; however, it is possible that staining technique or tumor subtype or quantity of amyloid present may account for the lower detection of amyloid observed by some of the researchers. Amyloid in basal cell carcinoma specimens was observed to be present more frequently in older patients who had tumors with less aggressive histology patterns. Nodular basal cell carcinoma was the most common subtype of tumor with amyloid deposits whereas superficial basal cell carcinoma was the least frequent subtype. The amyloid deposits were usually identified on hematoxylin and eosin-stained sections and confirmed by using stains that allowed for easier visualization of the amyloid. The amyloid deposits were most commonly located in the stroma between the tumor aggregates; other locations included the papillary dermis above the carcinoma, the dermis at the advancing edge of the tumor and within the aggregates of basal cell carcinoma. Many of the basal cell carcinomas with amyloid deposits, similar to the reported patient, also contained solar elastosis. The origin of the amyloid deposition in these tumors is secondary amyloid AA protein from keratin derived from the epithelial cells overlying the basal cell carcinomas. The presence of amyloid deposition does not alter the management of these basal cell carcinomas; the treatment of the tumor is the same as when the basal cell carcinoma does not contain amyloid deposition.

Cutaneous amyloidosis: a concept review

Concepts and semantics are crucial for good communication between clinicians and pathologists. Amyloidosis was described more than 150 years ago. Therefore, the terminology related to it is abundant, varied, and sometimes complex. In this report, we intend to discuss several terms related to the disease, with special emphasis on cutaneous amyloidosis. We present a review, from Virchow to present, of the concepts related to amyloidosis: its nature, the classification of cutaneous forms of the disease, and the techniques used in its diagnosis.

Amyloidomas of soft parts: diagnosis by fine-needle aspiration

A tumoral mass of amyloid (amyloidoma) arising in the soft tissues of the distal extremities is exceedingly unusual, and applying the fine-needle aspiration (FNA) biopsy technique to specifically diagnose this condition is even more infrequent. Herein, we report an example of two separate amyloidomas arising in the right calf of an otherwise asymptomatic elderly man who was referred to the sarcoma clinic because these masses clinically and radiographically simulated a malignant neoplasm. The fine-needle aspirate yielded amorphous, acellular, dense blue material on Romanowsky-stained smears and smudgy acellular cyanophilic material on Papanicolaou-stained smears. The aspirate procured cell-block contained hyalinized eosinophilic acellular material on H&E stain that was Congo-red positive and displayed yellow-green birefringence with polarization. Unlike prior assertions to the contrary, a diagnosis of amyloidoma is possible using FNA cytopathology even in patients without a known underlying amyloidogenic disorder.

Biochemical and immunohistochemical characterization of the amyloid in canine amyloid-producing odontogenic tumor

The amyloid of canine amyloid-producing odontogenic tumor (APOT) was evaluated biochemically and immunohistochemically. The N-terminal amino-acid sequence of purified amyloid protein from a canine APOT was strikingly similar to the sequence in both rat ameloblastin and porcine sheathlin. Immunohistochemically, the amyloid in APOT from 9 dogs was strongly reactive with anti-rat ameloblastin, anti-porcine sheathlin, and anti-canine APOT amyloid and weakly reactive with anti-porcine amelogenin but negative for antibodies to cytokeratins, vimentin, desmin, alpha-smooth muscle actin, amyloid A, glial fibrillary acidic protein, or S100 protein. The neoplastic epithelial cells of APOT were focally reactive with antibodies to ameloblastin, sheathlin, amelogenin, and canine APOT amyloid. The similarity in amino-acid sequence of the amyloid protein of canine APOT to that of enamel proteins, such as ameloblastin, sheathlin, and amelogenin, and the expression of these antigens in both APOT amyloid and in the neoplastic cells suggest that the amyloid of canine APOT is derived from enamel proteins secreted by ameloblasts.

Clinical and histopathologic findings of superficial basal cell carcinoma: A comparison with other basal cell carcinoma subtypes

BACKGROUND

Basal cell carcinoma (BCC) is the most common cancer in white populations. However, BCC is uncommon in Taiwan, and its subtype, superficial BCC (SBCC), is even less common. The characteristics of these 2 cancers in Taiwanese have never been analyzed before. Our purpose was to study the clinical and histopathologic features of SBCC in comparison with other BCC subtypes (OBCC).

METHODS

Thirty Taiwanese patients with SBCC from 1974 to 2003 were retrospectively examined at Taipei Veterans General Hospital. We analyzed the age, gender distribution, site of the lesions, clinical appearance, incidence of metastasis, and the proportion of secondary amyloid deposits. We then compared these features with those of 354 Taiwanese patients with OBCC.

RESULTS

Compared with the black pearly appearance of OBCC, erythematous plaques or patches with multiple tiny blackish papules were the most common clinical appearance of SBCC. Tumor size was significantly larger than OBCC (p < 0.05). The trunk was the most common area where SBCC arose. Conversely, OBCC occurred mainly on the head and neck (p < 0.001). Females were significantly younger than males in both SBCC and OBCC groups (p < 0.05). The frequency of secondary amyloid deposits was lower in SBCC than OBCC (p < 0.05).

CONCLUSION

The unique findings of SBCC would help to classify the subtypes of BCC. The mechanism of development of each subtype is worth further investigation in the future.

Cytokeratin contents of basal cell carcinoma, epidermis overlying tumour, and associated stromal amyloidosis: an immunohistochemical study

Cytokeratins (CKs) are expressed specifically in the cytoplasm of epithelial cells. We investigated the expression of CKs immunohistochemically in basal cell carcinomas (BCCs), epidermis overlying tumour, and skin tumor-associated amyloidosis (STA). Twenty cases of BCC, 11 of which had STA were included to the study. The primary antibodies of CK1-8 (AE3), CK10 (DEK-10), CK14 (LL002), CK17 (E3), CK18 (DC10), CK19 (KS19.1), CK 5/6/18 (LP34), CK8/18 (5D3) were applied to the section immunohistochemically. In BCCs without STA, CK1-8, CK14 and CK17 antibodies were expressed by tumour tissue in all biopsy specimens. In the BCCs with STA, tumour tissue was immunoreactive always with CK1-8 and CK17 antibodies, and commonly immunoreactive with anti-CK 14 antibody. In the epidermis overlying tumour tissue, there was positive immunoreactivity with anti-CK 1-8, CK 5/6/18, CK 10 and CK 14 antibodies in all biopsy specimens. Anti-CK 17 antibody was also positive in 17 biopsy specimens. STA is immunoreactive with anti-CK1-8 in all specimens. There was mild staining with anti-CK5/6/18 and with anti-CK19 whereas no immunoreactivity with anti-CK10 and CK18 antibodies was found. In conclusion, we could not find a significant CK expression difference between BCCs with and without STA. Weak positivity and a few number of CKs were shown in STA when compared with those of BCC and epidermis overlying tumour tissue expressing the more variable CKs. Interestingly, although CKs coexpressed in pairs consisting of one basic and one acidic CK, we detected predominantly basic CKs in STA.

Polarization-sensitive optical coherence tomography of invasive basal cell carcinoma

Skin cancer is the most common human malignancy, with basal cell carcinoma (BCC) the most frequent type. Aggressive forms of BCC are associated with extensive dermal invasion and destruction of collagen. Surgery is the most common treatment, but identification of tumor borders is a challenge. Polarization-sensitive optical coherence tomography (PS-OCT) is an optical method to examine collagen birefringence. To date, it has not been exploited for cancer management. As part of a pilot exploratory study to examine the use of OCT in skin cancer, we examined several tumors that pose a challenge to the surgeon due to their large size and histological subtype. In normal perilesional skin, OCT identifies epidermal and dermal structure; PS-OCT identified dermal birefringence. In BCC, tumors lost normal structure and gained the appearance of lobular impressions. PS-OCT identified an alteration of dermal birefringence. Examination of a border area revealed a gradual transition from more normal appearing image to frank tumor. These results indicate that PS-OCT can identify features that distinguish normal skin from tumor and may have the potential to guide surgeons in the treatment of aggressive skin cancer.

Immunohistochemical study of cytokeratins in amyloid deposits associated with squamous cell carcinoma and dysplasia in the oral cavity, pharynx and larynx

The frequency of amyloid deposits associated with squamous cell carcinoma (SCC) and dysplasia in the oral cavity, pharynx and larynx was examined. In addition, the origin of amyloid proteins by immunohistochemical staining with a panel of anticytokeratin monoclonal antibodies was investigated. Amyloid deposits were found in eight of 73 (11.0%) SCC and one of seven (14.3%) dysplasias in the oral cavity, in eight of 22 (36.4%) SCC and zero of two (0%) dysplasias in the pharynx, and in 22 of 37 (59.5%) SCC and four of 10 (40.0%) dysplasias in the larynx. Eight of 12 different cytokeratin (CK) antibodies reacted with these deposits: 34 beta E12 (CK1, -5, -10, -14) reacted with amyloid deposits in 19 of 19 cases (100%), LL002 (CK14) in eight of 18 cases (44.4%), MNF116 (CK5, -6, -8, -17) in eight of 19 cases (42.1%), D5/16B4 (CK5, -6) in five of 18 cases (27.8%), DE-K10 (CK10) in four of 17 cases (23.5%), RCK108 (CK19) in three of 18 cases (16.7%), 34 beta B4 (CK1) in three of 19 cases (15.8%) and AE8 (CK13) in two of 17 cases (11.8%). These antibodies always reacted with the cytoplasm of squamous cell lesions. Amyloid deposits in two cases contained a CK5 and CK14 pair, and in another two cases they contained both a CK5 and CK14 pair, and a CK1 and CK10 pair. Anti-CK antibodies, including OV-TL12/30 (CK7), c-51 (CK8), DC10 (CK18) and IT-Ks20.8 (CK20) did not react with the amyloid deposits. We conclude that the amyloid deposits associated with SCC or dysplasia in the oral cavity, pharynx or larynx were derived from CK of cancer cells and that some amyloid deposits might be assembled by two or more different CK.

Amyloid deposition in basal cell carcinoma: a cause of apparent lack of sensitivity to radiotherapy

We describe a patient with a large nodular basal cell carcinoma (BCC), which was excised following apparent failure to respond to radiotherapy. Histological examination of the fully excised lesion demonstrated a solid mass of amyloid, which stained positively for cytokeratins, but there was no residual BCC.

An immunohistochemical study of cytokeratins in skin-limited amyloidosis

The frequency of amyloid deposits in cases of seborrheic keratosis was investigated In addition, the origin of amyloid protein(s) in lichen amyloidosis, macular amyloidosis and seborrheic keratosis was studied by immunohistochemical staining using a panel of anti-cytokeratin (CK) monoclonal antibodies. Amyloid deposits were found in 41 of 327 specimens (12.5%) from 301 cases of seborrheic keratosis. Amyloid deposits in seborrheic keratosis reacted with 6 of 12 CK antibodies and in lichen and macular amyloidosis (20 specimens) reacted with 5 of 12 CK antibodies. In seborrheic keratosis, antibody DE-K10 (labeling CK10) reacted with amyloid in 17 of 36 cases, antibody 34betaE12 (labeling CK1, 5, 10, 14) reacted in 33 of 39 cases, and antibody MNF116 (labeling CK5, 6, 8, 17) reacted in 32 of 35 cases. Among 20 specimens from lichen and macular amyloidosis, the three antibodies reacted with amyloid in the following rates: 1 with antibody DE-K10, all 20 with antibody 34betaE12, and 6 with antibody MNF116. These results suggest that amyloid deposits in seborrheic keratosis and lichen and macular amyloidosis may derive from epidermal cytokeratins.

Fine-needle aspiration cytology of amyloid associated with nonneoplastic and malignant lesions

To assess the value of fine-needle aspiration (FNA) cytology for the diagnosis of amyloid, we retrospectively studied all FNA cases diagnosed as having amyloid during a 6-yr period (1990-1996). FNA was performed on both superficial and deep locations. A total of 6 cases containing amyloid was studied, including primary medullary thyroid carcinoma, metastatic medullary thyroid carcinoma to a vertebrae, multiple myeloma, squamous-cell carcinoma of the lung metastatic to a hilar lymph node, primary pulmonary amyloid, and amyloid tumor in a vertebral body in a patient with primary systemic amyloidosis. Despite the location or disease association, the cytologic appearance of amyloid in all cases was similar. On Diff-Quik stain, amyloid appeared as amorphous, irregular, waxy basophilic to metachromatic clumps of material. Papanicolaou stain revealed cyanophilic to organophilic clumps of material with occasional prominent fissures. In all 6 cases, amyloid was confirmed by Congo red stain and in 3 cases by a thioflavin T stain. In 4 of the 6 cases (67%), amyloid was associated with an underlying malignancy. In 3 cases malignant cells were admixed with the amyloid, and in another case malignancy was present at a distant site. We conclude that FNA biopsy is a helpful initial procedure for the evaluation of patients with amyloid deposits. The clinical implications of amyloid found in any particular body site include both benign and malignant conditions. The presence of an associated neoplasm must be especially considered in the differential diagnosis of amyloid deposits.

Basal cell carcinoma metastatic to the salivary glands: differential diagnosis in fine-needle aspiration cytology

A disparate group of salivary gland neoplasms is characterized by small, uniform, hyperchromatic, basaloid cells. This "small blue cell" pattern is most common in non-Warthin's types of monomorphic adenoma, or in adenoid cystic carcinoma. Small cell anaplastic carcinoma (primary or metastatic), metastatic basaloid squamous cell carcinoma, basal cell adenocarcinoma, and metastatic nasopharyngeal carcinoma are rarely encountered but may present a cytologically similar appearance. We report one female and two male patients (median age = 84 yr) with cutaneous-type basal cell carcinoma (BCC) aspirated from metastatic deposits in the parotid (2 cases) or the submandibular (1 case) gland. One was correctly classified at the time of aspiration, based on a previous history of multiple facial BCC. One was interpreted as carcinoma, the previous history being unavailable at the time of FNA. Smears in these two cases show necrosis and rare keratotic cells. The third cases was mistaken for pleomorphic adenoma (PA); the smears showed metachromatic fragments of collagenous tumor stroma that were misinterpreted as the matrix material typical PA. Similar material was identified in the other two cases. When the "small blue cell" pattern is encountered in salivary bland cytology, one should consider BCC, especially if necrosis is identified. The desmoplastic tumor stroma of BCC may mimic the chondroid matrix of PA. Careful consideration of previous history is very important.

Basal cell carcinoma with hyaline inclusions

A 69 yr old man had a 4 mm basal cell carcinoma completely excised from the chin. Numerous hyaline cytoplasmic inclusions were contained within the tumor cells. The inclusions stained intensely red with Masson's trichrome, and immunocytochemically there was prominent rim labelling for keratins (bovine, callus and AE1/3) and muscle-specific actin, the latter more faintly decorating the centre of some inclusions. The inclusions were negative for antibodies to cytokeratin Cam5.2, epithelial membrane antigen (EMA), vimentin, S100, neurofilaments, glial fibrillary acidic protein (GFAP) and carcinoembryonic antigen (CEA) and there was no post Congo red apple green birefringence to indicate amyloid. Ultrastructure indicated the inclusions were composed of proteinaceous material surrounded by a defined rim of tonofilaments in cells showing no degenerative features. The findings suggested aberrant tumor cell keratinization. Familiarization with this rare variant of a common cutaneous carcinoma will alleviate diagnostic difficulties that may arise, particularly in superficial tumor curettage.

Chronic myelomonocytic leukemia associated with primary amyloidosis

A case of chronic myelomonocytic leukemia (CMML) associated with primary amyloidosis (AL) is presented. Hepatosplenomegaly, macroglossia, and xanthelasma were the major physical findings. Laboratory tests showed macrocytic anemia, thrombocytopenia, monocytosis and a bi-clonal gammopathy. Early monocytes and monoblasts were noted in the bone marrow aspiration biopsy. Cytogenetic evaluation showed a clonal deletion of chromosome 21 long arm (21q-). Amyloid was present in the liver, tongue and xanthelasma. In addition, the patient was noted to have osteosclerosis of the lower extremities. Treatment with prednisone and colchicine resulted in a subjective response. The unusual association of CMML, and primary amyloidosis is discussed.

Secondary localized cutaneous amyloid in Bowen's disease

A case of Bowen's disease is described in which striking quantities of amyloid were detected in the papillary dermis visualized easily by routine haematoxylin and eosin staining. The material showed positive labelling with an antikeratin monoclonal antibody consistent with the proposed origin of the amyloid as degenerate keratinocytes. The pathobiology of amyloid associated with dysplastic squamous lesions is discussed.

Localized amyloidosis in squamous cell carcinoma of uterine cervix: electron microscopic features of nodular and star-like amyloid deposits

An ultrastructural study of amyloid deposits in four cases of squamous cell carcinoma of uterine cervix was performed. The amyloid deposits reacted with anti-keratin antiserum on frozen sections. Amyloid deposits showed nodular (4 cases) and star-like forms (3 cases). Nodular amyloid deposits were composed of slightly whorled fibrils, measuring 7-10 nm in width. Some of them contained cellular debris and thicker, more electron-dense filaments than amyloid fibrils. In three cases, filamentous tumour cells and filamentous masses were observed together with amyloid. Star-like amyloid deposits were composed of bundles of straight amyloid fibrils. Some of the tumour cells in contact with star-like amyloid deposits had deep cytoplasmic invaginations, where closely packed amyloid fibrils were arrayed in parallel fashion. In addition, a few tumour cells had membrane-bound amyloid fibrils in the cytoplasm. It is suggested that nodular amyloid deposits are derived from the tumour cells through filamentous degeneration. Amyloid fibrils in star-like amyloid deposits are thought to be formed within the cytoplasm or in the vicinity of invaginated cytoplasmic membranes of the tumour cells.

Amyloid stroma in meningiomas

Twenty-three cases of meningiomas with psammoma bodies (PBs) and 15 without PBs have been studied using histochemical, ultrastructural and immunohistochemical methods for amyloid. Amyloid was found in all cases showing PBs and in only 5 cases in the group devoid of PBs. Meningiomas may contain amyloid in their stroma.

BCC-associated amyloidosis with a peculiar pattern of deposition

An 83-year-old Japanese woman with lepromatous leprosy had been treated in a leprosarium. More than 10 years ago, she developed a dome-like brown tumor on the dorsum of the nose which showed the histology of basal cell carcinoma. The lesion was a well bordered, rounded tumor with tumor cell nests on its periphery extending toward the center as cords of tumor nest and with amyloid depositions between the cords. The tumor nests and amyloid lessened toward the center of the tumor, being replaced by collagen fibers. Amyloidosis showing this peculiar pattern of transition was reported with a review of published cases.

Primary localised cutaneous amyloidosis in Malaysians

A review of consecutive biopsies from 85 Malaysian patients with primary localised cutaneous amyloidosis (PLCA) revealed 63 with papular amyloidosis (PA) and 22 with macular amyloidosis (MA). PLCA appeared to affect the Chinese more frequently than the other major ethnic groups but MA was more common than expected among the Indians. Of patients with PA, one had systemic lupus erythematosus, one scleroderma and in another, connective tissue disease was suspected. MA was not found to be associated with any other disease. Histologically, PA differed from MA by the larger size of amyloid deposits in the papillary dermis. There was no difference in their tinctorial and immunohistochemical characteristics. Deposits were permanganate-resistant and negative for AA protein, immunoglobulin light chains and keratin. A few cases exhibited positively for cytokeratin. Strong immunoreactivity for AP protein was observed. PA and MA appear chemically similar and are likely to be of epidermal origin.

The pattern of amyloidosis in a Malaysian patient population

Congo red screening of 27,052 routine biopsy specimens from 22,827 patients over a 5 1/2-year period in the Department of Pathology, University of Malaya detected 186 cases of amyloidosis. The categories of amyloidosis encountered and their prevalences in relation to each other were: systemic AL (5.9%); systemic AA (3.2%); isolated atrial (14%); primary localized cutaneous (7.5%); other primary localized deposits (3.2%); localized intratumour (58%); and dystrophic (8.6%). A third of patients with systemic AL amyloidosis had coexistent immunocyte abnormality. The commonest underlying pathology for systemic AA amyloidosis was leprosy. Notable among the types of localized amyloidosis revealed by this study were isolated atrial amyloidosis, which appeared to complicate chronic rheumatic heart disease, and intratumour amyloidosis complicating nasopharyngeal carcinoma. Other tumours in which amyloid deposits were observed included basal cell carcinoma, islet cell tumour and medullary carcinoma of the thyroid. Dystrophic amyloidosis was observed in fibrotic tissues, such as damaged cardiac valves and osteoarthritic joints. Heredofamilial amyloidosis, senile systemic amyloidosis and degenerative cerebral amyloidosis were notably absent from this study.

Biology of basal cell carcinoma (Part I)

Basal cell carcinoma is the most common malignancy in humans. Although rarely metastatic, it is capable of significant local destruction and disfigurement. This two-part article reviews the current understanding of basal cell carcinoma biology. Part I examines significant clinical, histologic, and ultrastructural features that relate to invasive potential. Genetic characteristics, including tumor growth rate, chromosomal abnormalities, and oncogene presence, are discussed, and expression of important cell and matrix proteins, including keratin, fibronectin, and HLA antigens, are reviewed. Further topics to be explored in Part II include host immunologic responses, theories of pathogenesis, and valuable second-line therapeutic regimens for treatment of multiple cancers.

Amyloid deposits in basal cell carcinoma of the skin. A pathologic study of 199 cases

Deposits of amyloid were detected in 101 of 199 basal cell carcinomas (51%). The frequency of amyloid deposits in solid, adenoid, and cystic histologic subtypes was slightly higher than overall, whereas in partial sclerosing and morphea-like tumors the frequency was much lower. The amyloid of basal cell carcinoma showed histochemical characteristics that were different from those of locally deposited amyloid in endocrine tumors such as medullary carcinoma thyroid and from those of "secondary" amyloid. No major differences in the histochemical characteristics, however, were observed between amyloid associated with basal cell carcinoma and myeloma-associated or "primary" amyloid. Nevertheless, immunohistochemical staining with rabbit antihuman keratin antibodies by the peroxidase antiperoxidase technique demonstrated positivity only in amyloid deposits associated with basal cell carcinoma and not in those of myeloma-associated amyloid. This evidence supports the concept that amyloid of basal cell carcinoma is produced in the stroma from degenerated epithelial cells through filamentous degeneration or apoptosis.

Basal cell carcinoma xenografts in nude mice: studies on epithelial differentiation and stromal relationships

Thirty-three basal cell carcinomas (BCC) were transplanted into athymic mice, and foci of tumour were identified in 17 grafts recovered after intervals of 2-5 months. Fifteen of these xenografts contained apparently normal differentiated epithelia, considered to derive from elements within the original tumours. The level of differentiation was very close in original and corresponding xenograft BCC. Morphologically recognizable 'specialized' stroma was present in some but not all xenografted BCC, and was also present in some grafts containing only differentiated elements. A monoclonal antibody specific to human type IV collagen showed intact epithelial and also vascular basement membranes within the graft. Surprisingly, mouse cells were found to line these vessels, and the stroma around normal and neoplastic epithelial islands was a mixture of mouse and human cells, with no consistent composition. These observations question the proposed dependence of BCC on its 'specialized' stroma.

An investigation of the protein components of amyloid using immunoperoxidase and permanganate methods on tissue sections

Amyloid deposits in tissue from 8 patients with generalized primary amyloidosis, 11 patients with generalized secondary amyloidosis, 11 nasopharyngeal carcinomas, 11 basal cell carcinomas, 4 islet cell tumours, 4 medullary carcinomas of the thyroid and 9 cases of lichen amyloidosis were studied using the indirect immunoperoxidase and peroxidase-antiperoxidase methods with specific antisera against Amyloid A (AA) protein and human immunoglobulin lambda and kappa light chains. The permanganate method of Wright was also applied to tissue sections. Positive staining for AA protein was observed only in secondary amyloidosis. There was excellent correlation between AA positivity and permanganate sensitivity. Positivity for immunoglobulin light chains was not observed in secondary amyloidosis but was noted in 5 (63%) cases of primary amyloidosis and 18-27% of intratumour amyloidosis. Lichen amyloidosis did not stain for AA protein or light chains. It is shown that assessment of the permanganate reaction and AA positivity of amyloid deposits can reliably differentiate secondary from primary amyloidosis and may contribute significantly to selection of patients for appropriate therapy.