Indian Journal of Pathology and Microbiology

: 2020  |  Volume : 63  |  Issue : 1  |  Page : 128--130

Giant variant of acquired perforating dermatosis, clinically masquerading as a sarcoma: A report of a rare case

Lalani De Silva, MD S. Lokuhetty 
 Department of Pathology, Faculty of Medicine, University of Colombo, Sri Lanka

Correspondence Address:
Lalani De Silva
Department of Pathology, Faculty of Medicine, University of Colombo
Sri Lanka


Acquired perforating dermatosis is a group of disease characterized by transepidermal elimination of altered dermal constituents of unknown pathogenesis. The giant variant was first described in 2006, as an emerging entity with seven reported cases to date. Here is an 83-year-old male presented with a 4-year history of gradually enlarging soft tisssue mass with ulcerartions at the left knee joint. Imaging revealed an extra-articular, single, heterogeneous, multinodular mass, suspicious for a soft tissue sarcoma. Wide local excision of the mass showed fleshy, hemorrhagic nodules communicating with epidermal ulcers. Microscopy showed cystic spaces straddling dermis and subcutis, containing eosinophilic, amorphous, granular material extruding through epidermal craters, surrounded by exuberant myofibroblastic proliferation. Trichrome and van-Gieson stains confirmed that the extruded material is collagen and the histology was compatible with the giant variant of acquired perforating collagenosis. Awareness of histological appearance prevents misdiagnosis and overtreatment of this entity, masquerading as a sarcoma clinically.

How to cite this article:
Silva LD, S. Lokuhetty M D. Giant variant of acquired perforating dermatosis, clinically masquerading as a sarcoma: A report of a rare case.Indian J Pathol Microbiol 2020;63:128-130

How to cite this URL:
Silva LD, S. Lokuhetty M D. Giant variant of acquired perforating dermatosis, clinically masquerading as a sarcoma: A report of a rare case. Indian J Pathol Microbiol [serial online] 2020 [cited 2022 Oct 5 ];63:128-130
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Perforating dermatosis is a term describing a group of diseases encompassing perforating collagenosis, elastosis perforans serpiginosa, perforating folliculitis, and Kyrle's disease.[1] It is characterized by transepidermal elimination of altered dermal substances. The origin of the disease is either inherited or acquired. The inherited form is described in childhood, associated with a positive family history while the acquired form is seen in adults with systemic illnesses. The giant variant of acquired perforating dermatosis is identified as an emerging entity with only seven reported cases in the literature to the best of our knowledge.[2],[3],[4],[5]

 Case History

An 83-year-old male sought consultation with a 4-year history of a gradually enlarging mass lesion on the anterior aspect of the left knee, with rapid enlargement, pain, and restricted joint movement over the last 3 months.

He was physically active and was diagnosed to have diabetes for 1 year and was on dietary control. Physical examination revealed a large, firm, soft tissue mass over the left knee joint with epidermal ulceration forming craters. Basic serological investigations revealed normal leucocyte count, c-reactive protein, liver functions, and renal functions.

Magnetic resonance imaging study reported a heterogeneous, multinodular mass located in the soft tissue anterior to the left patella. There were thick septa and foci of hyperintensity. The mass measured 10.0 × 8.0 × 4.0 cm. It did not extend to the patella or the knee joint. Joint effusions or bone erosions were absent. The radiological impression favored a soft tissue sarcoma [Figure 1]a.{Figure 1}

Initial tru-cut biopsy was inconclusive. A wide local excision of the lesion was performed subsequently based on the clinical and radiological findings. Gross examination of the resected specimen revealed a large soft tissue mass with a skin ellipse containing two ulcerated nodules with central craters. These nodules measured 8.0 cm and 7.0 cm in maximum diameter. Cut surfaces showed multinodular mass with three fleshy, hemorrhagic nodules communicating with epidermal craters [Figure 1]b.

Microscopy revealed cystic spaces straddling dermis and subcutis containing eosinophilic, amorphous, granular material extruding out through the epidermal craters. The cysts were surrounded by an exuberant myofibroblastic proliferation and foreign body giant cell reaction with foci of calcification. Inflammation was minimal and granulomata were absent.

Masson trichrome and Verhoeff-van Gieson stains confirmed that the extruded material was composed of collagen. The histomorphological features confirmed the diagnosis of giant variant of acquired perforating collagenosis [Figure 2]. The patient is well following surgery with no new lesions over the past 6 months.{Figure 2}


Perforating collagenosis was first described in 1967 by Mehregan et al. as transepidermal elimination of altered dermal collagen.[6]

It was diagnosed initially as an inherited, autosomal recessive condition affecting children, termed as primary reactive perforating collagenosis. A similar form of disease was described sporadically in adults in association with systemic illnesses. This latter condition was first reported by Rapini et al. as acquired perforating dermatosis in 1989.[7] More recently, a rare giant variant of acquired perforating dermatosis was described by Hoque et al. in 2006.[2] This variant is characterized by larger umbilicated lesions with central keratotic plugs of at least 1–2 cm in diameter.

Diagnosis of acquired perforating dermatosis requires three specific diagnostic criteria. These include[8]

Histopathological finding of transepidermal elimination of necrotic basophilic collagen bundles into a cup-shaped epidermal depressionUmbilicated papules or nodules with a central adherent keratotic plugOnset of the lesions after 18 years of age.

The acquired perforating dermatosis is identified in association with a variety of systemic conditions. Diabetes mellitus and end-stage renal disease are the most common associations. Others include immunodeficiency, scabies, sclerosing cholangitis, breast carcinoma, papillary thyroid carcinoma, lymphoma, and Poland syndrome.[1],[4],[8]

The classic acquired perforating collagenosis clinically present as extensively pruritic papules of 1–10 mm size with central epidermal craters.

Literature revealed a total of seven patients including the initial report of four patients with giant variant of acquired perforating dermatosis and three isolated case reports.[2],[3],[4],[5] The ages of affected patients ranged from 37 to 83 years (mean: 62 years). The majority had diabetes mellitus (75%) and renal impairment (50%). All patients had involvement of extremities (100%) and five of them had trunk involvement (62.5%). The extruded material was collagen in seven patients and one had disease similar to elastosis perforans serpiginosa. None had presented with a soft tissue mass, clinically and radiologically masquerading as a soft tissue sarcoma, as in this case [Table 1].{Table 1}

The exact pathogenesis of this entity is uncertain, whereas several theories have been described. As the disease is associated with intense pruritus and the extremities and trunk been the main sites where the patient can reach for scratching, superficial trauma to the epidermis and dermal substances is recognized as the key factor in the pathogenesis.[9],[10] A synergistic action is speculated in diabetics due to microvasculopathy associated ischemic injury to dermal substances.[10] Ultrastructural study reveals three stages of development. In the first developing stage, the epidermis regenerates in between the reticular dermis and the necrotic mass and the collagen bundles in the reticular dermis are in continuity with those in the necrotic mass. In the second stage, the regenerated epidermis makes a thick horney layer lifting up the collagen bundles and necrotic mass through epidermal channels. In the third mature stage, the eliminating collagen bundles are surrounded by fibroblasts.[11]

Various treatment options have been described though none are regarded as the gold standard. Treatment with Allopurinol is reported to be effective in a majority of patients with acquired perforating collagenosis, including four patients with the giant variant.[2],[3],[12] The therapeutic effect of Allopurinol is attributed to the reduction of formation of oxygen-free radicals by inhibitory effect on xanthene oxidase. This restricts the collagen damage caused by oxygen-free radicals. In addition, it reduces the cross linking of collagen fibers due to advanced glycosylated end products in diabetic patients.[2] Other treatment options shown to be variably effective include topical steroids, topical and systemic retinoids, keratolytics, Rifampicin, ultraviolet B phototherapy, Psoralen ultraviolet A, and cryosurgery.[5] None of these medical treatment options were tried in this patient prior to surgical excision.

The giant variant of acquired perforating dermatosis is an emerging entity with a range of clinical presentations including a soft tissue mass with ulcerating skin nodules masquerading as a sarcoma, as in this case. Histopathological findings are paramount in arriving at the correct diagnosis.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.


Dr. Ananda Perera. Consultant orthopaedic surgeon, Sri Jayewardenepura General Hospital, Sri Lanka.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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