APACHE no more
By Warren R. Heymann, MD
Dec. 4, 2017
Credit: JAAD
This commentary is about being DC (Dermatologically Correct), not PC (Politically Correct as in the Washington Redskins controversy). The time to retire the acronym APACHE (Acral Pseudolymphomatous Angiokeratoma of Children) is overdue.
APACHE was an acronym coined by Ramsay et al, when they described a unilateral eruption that developed in 5 children (mean age 6 years, range 2 – 13 years), that were clinically suggestive of angiokeratomas (“in that they were bright red or violaceous and had a keratotic surface or collar around their base”). Histologically, there was a dense infiltrate composed of lymphocytes, plasma cells, and some histiocytes, but no eosinophils [subsequent reports by other authors would include eosinophils]; there was an equal number of B and T cells, with a preponderance of suppressor/cytotoxic to helper T cells. This was accompanied by thick-walled blood vessels lined by plump endothelial cells. For those patients who were not treated with curettage, the lesions were noted to last for up to 14 years. The authors recognized that this is a benign disorder, and urged that it be recognized to avoid any overzealous treatment. (1)
Subsequently, there have been reports of identical lesions occurring in adults and in non-acral sites. (2) It has also been described in the elderly, including a report of a 76 year-old man who presented with a 5-year history of progressively increasing asymptomatic dusky dome-shaped papules and plaques of his upper and lower extremities. The authors reviewed all of the adult cases reported in the literature, comparing them to the classical variant in children, and found no significant difference between the groups. (3)
Like all cases of pseudolymphoma, the diagnosis may be challenging, requiring careful clinical-pathologic correlation. This is exemplified by the case of a 59-year-old woman who presented with an unusual unilateral, clustered aggregate of scaly violaceous papules on the toe with an indolent course. Skin biopsy showed a prominent vascular proliferation associated with a dermal infiltrate of monoclonally rearranged T-follicular helper phenotype T-cells, in keeping with a CD4+ small/medium T-cell lymphoproliferative disorder (SMPTC-LPD). Based on the unique clinical morphology and distribution of the lesions, a clinicopathologic diagnosis of acral angiokeratoma-like pseudolymphoma was favored. [I’m not sure I would have reached the same conclusion, however, the authors note that “the distinction of SMPTC-LPD from pseudolymphoma is challenging and it is debated whether it should be considered a lymphoma at all.”](4)
The etiology of these lesions remains an enigma. The polyclonal nature of the infiltrate suggests that this is a reactive process. Most authorities agree that this is a pseudolymphoma, not a vascular lesion. The vasculature has been reported as staining positive for CD 34 and WT-1 (confirming that these are blood vessels), but variably for podoplanin (D2-40, for lymphatic cells). (5, 6). The expression of WT-1 suggests that these vessels are proliferative and reactive, possibly secondary to hypoxia, rather than representing a vascular malformation. (5). The possibility of a genetic predisposition has been suggested, based on the report of the appearance of an APACHE-like eruption in adult identical twins. (7)
Therapeutic considerations may include topical or intralesional steroids, cryosurgery, curettage, surgical excision, or radiation therapy. Regardless of the modality, lesions may recur. (5)
The acronym APACHE was reasonable in 1990 based on the initial report, but it is no longer tenable for the following reasons: 1) Although most lesions are acral, they may be distributed on the trunk; 2) These lesions are pseudolymphomas — while it may be arguable if lesions resemble angiokeratomas clinically, they are certainly not angiokeratomas histologically. The term angiokeratoma clouds the true nature of these lesions; 3) While often seen in children, the disorder may be seen throughout life.
If not APACHE, what should these lesions be called? There have been many suggestions (see reference 2 for a detailed list), but I favor the term “small papular pseudolymphoma (SPP).” Only for those cases that perfectly match the original patients described by Ramsay et al (1), would I consider the diagnosis of the APACHE variant of SPP.
1. Ramsay B, et al. Acral pseudolymphomatous angiokeratoma of children. Arch Dermatol 1990; 126: 1524-5.
2. Wagner G, et al. Papular pseudolymphoma of adults as a variant of acral pseudolymphomatous angiokeratoma of children (APACHE). J Dtsch Dermatol 2014; 12: 423-4.î
3. Chedraoui A, et al. Acral pseudolymphomatous angiokeratoma of children in an elderly man: Report of a case and review of the literature. Int J Dermatol 2010; 49: 184-8.
4. Geller S, et al. Acral angiokeratoma-like pseudolymphoma in a middle-aged woman. J Cutan Pathol 2017; 44: 878-81.
5. Lessa PP, et al. Acral pseudolynphomatous angiokeratoma: Case report and literature review. An Bras Dermatol. 2013; 88: 6 Suppl 1):39-43.
6. Fernandez-Flores A, et al. Expression of WT-1 by the vascular component of acral pseudolymphomatous angikeratoma of children. J Cutan Pathol 2015; 42: 50-5.
7. Fonia A, et al. Acral pseudolymphomatous angiokeratoma of children (APACHE)-like eruption in adult identical twins. Clin Exp Dermatol 2016; 41: 751-3.
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