Granuloma annulare: an immunohistochemical study

Mucin as a diagnostic clue in dermatopathology

Mucins are high-molecular weight glycoproteins typically found in normal skin in small amounts. There are several reports regarding different types of cutaneous mucinosis. In this report, we discuss mucins in dermatopathology as a diagnostic clue of some well-known entities and some less frequent cutaneous diseases. We also emphasize mucin as a sign in the differential diagnosis between conditions that show histopathological overlap. Lastly, we discuss the locations and circumstances in which mucin could be considered almost normal or physiological.

Histological and immunohistochemical study of granuloma annulare and subcutaneous granuloma annulare in children

BACKGROUND

The aim of this study was to investigate the histological and immunohistochemical features of granuloma annulare (GA) in comparison to deep granuloma annulare (DGA) and granulomatous dermatoses (GDs).

METHODS

Our material comprised 13 GA, 8 DGA and 1 atypical granuloma annulare (AGA) in a child with primary immunodeficiency, 10 cases of nonspecific GDs and 1 case of sarcoidosis with cutaneous involvement. The immunohistochemical streptavidin-biotin-Horseradish peroxidase (HRP) analysis was performed on paraffin sections for the detection of CD68/KP-1, CD68/anti-human CD68 clone PGM1 (PGM1), lysozyme, S-100 protein, CD1a, CD3, CD20/L-26, CD4 and CD8.

RESULTS

All 13 GA were characterized by typical palisading and interstitial granulomas. In 6 cases, the lesion extended to the subcutaneous fat, while a considerable perivascular lymphocytic infiltrate without any signs of vasculitis was observed in 10 cases. The DGA were located to the deep dermis and subcutaneous fat, showing palisading granulomas with central necrobiosis. Immunohistochemistry revealed a broad intense expression of CD68/PGM1 in the histiocytic population in all cases, a constant but fainter detection of CD68/KP-1 and a variable one of lysozyme. T-cell markers (CD3, CD4 and CD8) were mainly detected in the perivascular lymphocytic infiltrate of GA and DGA, with CD4+ T lymphocytes predominating over CD8+ in GA and DGA, while CD8+ T lymphocytes was the predominant population in AGA.

CONCLUSIONS

CD68/PGM1 is a sensitive and reliable histiocytic marker in confirming the histiocytic nature of equivocal GA and DGA, but the histiocytic immunoprofile is of no particular usefulness in differentiating GA from other GD.

Subcutaneous granuloma annulare in a child's palm: a case report

We present a rare case of subcutaneous lesions arising in the palm of a 4-year-old girl. Histologic examination of the biopsy specimens showed granulomatous inflammation with focal necrobiosis, which was consistent with subcutaneous granuloma annulare. Subcutaneous granuloma annulare is a self-limited disease and treatment is not required, although recurrence and/or multiple lesions are frequent.

Granuloma annulare with a mycosis fungoides–like distribution and palisaded granulomas of CD68-positive histiocytes

We describe 3 unusual cases of granuloma annulare with multiple macular lesions in a distribution that simulated mycosis fungoides in patients with no associated underlying diseases. Repeated biopsies showed typical well-formed palisading granulomas and no evidence of an atypical lymphocytic infiltrate. There was no vasculitis, neutrophilic, eosinophilic, or interstitial infiltrate. The patients had no associated underlying diseases. Most of the histiocytes in the palisading granulomas were strongly positive for CD68. The lymphocytes were a minor component of the granulomatous inflammation and were predominantly CD8(+) T-cells. The findings in these cases add to the spectrum of previously defined granulomatous eruptions of the skin.

Collagenolytic (necrobiotic) granulomas: part 1 - the ‘blue’ granulomas

A collagenolytic or necrobiotic non-infectious granuloma is one in which a granulomatous infiltrate develops around a central area of altered collagen and elastic fibers. The altered fibers lose their distinct boundaries and exhibit new staining patterns, becoming either more basophilic or eosinophilic. Within the area of altered collagen, there may be deposition of acellular substances such as mucin (blue) or fibrin (red), or there may be neutrophils with nuclear dust (blue), eosinophils (red), or flame figures (red). These color distinctions can be used as a simple algorithm for the diagnosis of collagenolytic granulomas, i.e. "blue" granulomas vs. "red" granulomas. Eight diagnoses are included within these two groupings, which are discussed in this two-part article. In this first part, the clinical presentation, pathogenesis, and histologic features of the "blue" collagenolytic granulomas are discussed. These are the lesions of granuloma annulare, Wegener's granulomatosis, and rheumatoid vasculitis. In the subsequent half of this two-part series, the "red" collagenolytic granulomas will be discussed; these are the lesions of necrobiosis lipoidica, necrobiotic xanthogranuloma, rheumatoid nodules, Churg-Strauss syndrome, and eosinophilic cellulitis (Well's syndrome).

Granuloma anular: distribuição tecidual dos dendrócitos dérmicos fator XIIIa+, das células dérmicas trombomodulina+ e de macrófagos CD68+

FUNDAMENTOS: Um subgrupo de células dérmicas relacionado a macrófagos expressa o fator pró-coagulante XIIIa enquanto outro subgrupo expressa o co-fator anticoagulante trombomodulina. Esses tipos celulares podem estar envolvidos em eventos de inflamação e reparo tecidual. OBJETIVOS: Investigar a participação de células dérmicas fator XIIIa+ e de células dérmicas trombomodulina+ (TM) no quadro histopatológico do granuloma anular que se caracteriza por necrobiose do colágeno e presença de infiltrado de macrófagos. MATERIAIS E MÉTODOS: O quadro histopatológico do granuloma anular observado em 23 fragmentos da pele obtida pela biópsia foi classificado de acordo com a presença de degeneração completa ou incompleta do colágeno e distribuição do infiltrado inflamatório. Dendrócitos dérmicos fator XIIIa+ e células dérmicas trombomodulina+ foram reconhecidos por meio de anticorpos próprios aplicados em protocolos de imuno-histoquímica; um marcador para macrófagos (CD68) também foi utilizado. Observou-se a distribuição dos subtipos celulares distintos, bem como realizou-se análise semiquantitativa. RESULTADOS: Dendrócitos fator XIIIa+ foram escassamente detectados, enquanto células trombomodulina+ e CD68+ representaram considerável proporção do infiltrado celular, observadas na posição periférica (arranjo em paliçada), entre fibras colágenas degeneradas ou mesmo difusamente distribuídas. Houve tendência de associação da semiquantificação alta de células trombomodulina+ com a semiquantificação baixa de dendrócitos fator XIIIa+ e com o tipo histológico II. Hiperplasia de dendrócitos dérmicos ao redor da lesão foi observada. CONCLUSÃO: A diferente distribuição tecidual de células fator XIIIa+ e TM+ pode refletir suas participações distintas e complementares no reparo do tecido dérmico e no processo evolutivo da lesão no granuloma anular.

Expression of the histiocytic marker PG-M1 in granuloma annulare and rheumatoid nodules of the skin

BACKGROUND

The expression of PG-M1, the most specific histiocytic marker, has not yet been studied in granuloma annulare (GA) and other palisaded granulomas of the skin. We evaluated the reactivity of PG-M1 with a series of GA and rheumatoid nodules (RN) to establish the sensitivity and potential usefulness of this marker in the diagnosis and characterization of these entities.

METHODS

Histological sections from 30 GA and 15 RN were immunostained with PG-M1. For comparison, additional sections were stained with KP-1 and lysozyme. The stains were recorded as negative, weakly positive (1+) and strongly positive (2+).

RESULTS

PG-M1 stained all cases of GA (100%). KP-1 and lysozyme stained 26 (86%) and 18 (60%) GA cases, respectively. PG-M1 exhibited a significantly stronger staining intensity (1.8 +/- 0.07) when compared with KP-1 (1.4 +/- 0.13) (p = 0.018) and with lysozyme (0.9 +/- 0.15) (p < 0.0001). All RN were stained by PG-M1 (100%). KP-1 and lysozyme stained 14 (93%) and six (40%) RN cases, respectively. PG-M1 staining intensity (1.6 +/- 0.13) was slightly higher than that of KP-1 (1.4 +/- 0.18) (p = 0.27) and significantly higher than that of lysozyme (0.4 +/- 0.13) (p < 0.0001).

CONCLUSIONS

PG-M1 is consistently and strongly expressed by the histiocytic population of GA and RN, being more sensitive and reliable than other histiocytic markers. We recommend its use in difficult cases in which the histiocytic nature of the lesion needs to be confirmed.

Interstitial mycosis fungoides, a variant of mycosis fungoides resembling granuloma annulare and inflammatory morphea

BACKGROUND

Interstitial mycosis fungoides (IMF) is a rare variant of mycosis fungoides that resembles the interstitial form of granuloma annulare and inflammatory morphea. IMF has received little attention in the literature.

METHODS

Clinical, histological, immunophenotypical, and genotypical findings of five cases of IMF were reviewed. The histological and immunophenotypical findings were compared with those of eight cases of interstitial granuloma annulare and six cases of inflammatory morphea.

RESULTS

Five patients with IMF presented with non-indurated, erythematous macules; ill-defined erythematous plaques with slight scale; and nodules on the trunk and proximal limbs. Two of five patients had a prior diagnosis of mycosis fungoides. Skin biopsies revealed a striking dermal interstitial infiltrate of lymphocytes with rare histiocytes that resembled the interstitial form of granuloma annulare or inflammatory morphea. Epidermotropic lymphocytes were present at least focally in all cases. A band-like lymphocytic infiltrate was observed in two of five cases. In contrast, many plasma cells and histiocytes were observed in cases of inflammatory morphea and interstitial granuloma annulare, respectively. With Movat-pentachrome stains, increased dermal mucin deposition was observed in two of five IMF cases, in all cases of interstitial granuloma annulare, and in one of six cases of inflammatory morphea. There was focal loss of elastic fibers in all cases of inflammatory morphea. Immunohistochemical studies of IMF highlighted a dominant population of T cells (CD3+) in the dermis and epidermis. In contrast, moderate numbers of B cells (CD20+) were admixed with T cells and plasma cells in inflammatory morphea. Almost equal numbers of histiocytes (CD68+) and T cells comprised the infiltrate of interstitial granuloma annulare. In two of five IMF cases, a clonal T-cell population was detected by PCR T-cell gamma gene rearrangement analysis.

CONCLUSION

Mycosis fungoides occasionally presents as an interstitial lymphocytic infiltrate that mimics granuloma annulare and inflammatory morphea. Hematoxylin & eosin (H&E) findings alone can sometimes distinguish the three disorders. Immunophenotyping and genotyping may be helpful in difficult cases.

Patch granuloma annulare: clinicopathologic study of 6 patients

BACKGROUND

Granuloma annulare is a common skin disorder that usually presents with smooth papules arranged as annular plaques. Variants, such as disseminated, subcutaneous, and perforating granuloma annulare, have been described.

OBJECTIVE

The purpose of this study is to describe the clinical and histologic features of a distinct patch form of granuloma annulare.

METHODS

The clinical and histologic features of 6 patients with patch granuloma annulare were evaluated.

RESULTS

Six women 27 to 72 years of age had patches on the extremities. Two patients also had a lesion on the trunk. Only one patient had annular patches. Histologic examination showed an interstitial infiltrate of lymphocytes and histiocytes with diffuse necrobiosis.

CONCLUSION

Patch granuloma annulare is a distinct variant with rather subtle clinical and histologic features. A high index of suspicion both clinically and histologically aids in making the diagnosis.

Deep granuloma annulare (pseudorheumatoid nodule) in children: clinicopathologic study of 35 cases

Deep granuloma annulare (DGA) is one of several lesions of skin and superficial soft tissues whose histologic character is a palisading granuloma with a small central focus of necrosis or necrobiosis. Unlike the other palisading necrobiotic lesions, DGA has a predilection for children in the first 5 to 6 years of life. A painless subcutaneous nodule(s) in the lower anterior tibial region or foot and the scalp, typically in the occiput, was the most common presenting feature in this study of 35 cases. Additional or recurrent lesions were reported in approximately 70% of cases with clinical follow-up. All lesions showed the presence of necrobiosis; however, one of the characteristic features was the multinodular character of the predominantly mononuclear cellular aggregates. The presence of vascular spaces at the periphery of the nodular profiles served as a clue to the diagnosis of DGA. The palisading arrangement of the mononuclear cells was evident only in those foci with central necrobiosis. A histiocytic disorder or fibrohistiocytic process was a common consideration in the differential diagnosis, especially in those cases with less apparent foci of necrosis. Palisading histiocytes with prominent eosinophilic cytoplasm and some nuclear atypism were problematic with regard to possible epithelioid sarcoma. Our study failed to identify any underlying or predisposing factors in the development of DGA. Despite the fact that DGA is a well-documented lesion in children, it occurs sufficiently infrequently that it is often not considered clinically when it presents as a subcutaneous mass or masses in a child. Its recognition by the pathologist is especially important as the occurrence of additional lesions in a high proportion of children can be anticipated without undue concern.

Mitotic granuloma annulare: a clinicopathologic study of 20 cases

The finding of mitotic figures in granuloma annulare (GA) has not been emphasized in the literature. We describe 20 cases of a cellular, mitotically active variant of GA; we defined this group as cases having > or = 1 mitosis per 10 hpf. Clinically, the lesions could not be distinguished from typical, localized GA: there were 9 males and 11 females with a mean patient age of 49 +/- 15 years (mean +/- SD), compared to 45 +/- 20 years in a randomly selected control group of 60 patients with GA, and no unusual sites of predilection were noted. Histologically, a classic, palisading granuloma pattern predominated (18/20 cases). Lesions were located in the mid-dermis and tended to be more cellular than typical GA. The histiocytes comprising the lesion often had enlarged nuclei and prominent nucleoli. The number of mitoses per 10 hpf was 3.0 +/- 1.5 (range 1.0-7.2), control group 0.3 +/- 0.5; occasional atypical mitotic figures were observed. The proliferative nature of these lesions was confirmed using MIB-1 staining; the percentage of MIB-1 positive cells ranged from 5%-29% (mean 15 +/- 6%). Mitotic GA must be distinguished histologically from neoplastic processes, in particular epithelioid sarcoma. We conclude that histiocytes in clinically typical GA can exhibit an increased mitotic rate. Recognition of this variant is important in order to avoid overdiagnosis of a malignant condition.

Interstitial granulomatous dermatitis with arthritis

BACKGROUND

Interstitial granulomatous dermatitis with arthritis is an uncommon systemic disorder involving the cutaneous and musculoskeletal systems. The eruption may mimic other dermatoses including granuloma annulare, erythema chronicum migrans, and the inflammatory stage of morphea. Key histopathologic characteristics, along with clinical correlation, allow accurate diagnosis.

OBJECTIVE

We describe the clinical, serologic, and histologic features in three patients with interstitial granulomatous dermatitis with arthritis.

METHODS

Skin biopsy specimens were examined and correlated with the clinical and laboratory findings.

RESULTS

Erythematous, annular, indurated plaques on the extremities were present in two women. An erythematous, papular eruption on the head and neck was present in a third patient. All patients had myalgia and migratory polyarthralgias of the extremities along with various serologic abnormalities. Histologic examination revealed a dense lymphohistiocytic interstitial infiltrate involving primarily the reticular dermis. Foci of necrobiotic collagen were present. Vasculitis was absent.

CONCLUSION

Interstitial granulomatous dermatitis with arthritis is unique multisystem disease with variable cutaneous expression. Abnormal serologic findings indicate a possible connection to collagen vascular disease.